Harness the Power of ASP.NET MVC, Web Api, OData, Kendo UI & RequireJS to Build an Easy & Maintainable SPA (for the .NET Developer) – Published

Apologize for the delay, the original article: “Harness the Power of ASP.NET MVC, Web Api, OData, Kendo UI & RequireJS to Build an Easy & Maintainable SPA (for the .NET Developer)” has now been published as “A .NET Developer Primer to Single-Page Applications (SPA)“.

Download: http://lelong37.files.wordpress.com/2014/03/msdn-mag-1403.pdf
Online: http://msdn.microsoft.com/en-us/magazine/dn605877.aspx
Source code: https://easyspa.codeplex.com
Live Demo: http://easyspa.azurewebsites.net/home/spa#/customer/index

3-4-2014 1-36-58 AM

Upgrading to Async with Entity Framework, Web Api, OData AsyncEntitySetController, Kendo UI, Glimpse & Generic Unit of Work Repository Framework v2.0

Update [11/18/2013]: Added mocked DbContext and DbSet and example Unit Tests using the mocks, download v2.1 https://genericunitofworkandrepositories.codeplex.com.

Thanks to everyone for allowing us to give back to the .NET community, we released Generic Unit of Work and Repository Framework v1.0 for four weeks and received 655 downloads and 4121 views. This post will also serve as the documentation for release v2.0. Thanks to Ivan (@ifarkas) for helping out on the Async development, Ken for debugging the Unit of Work life cycle management for use in web applications with DI & IoC (specifically with Entlib Unity v3.0) and scaling the framework to handle Bounded DbContexts, and to the Glimpse Team (@nickswan ) for helping out on getting Glimpse MVC4 working with MVC5, and providing guidance on how to leverage Glimpse EF6 to view SQL queries from EF.

This will be part six of a six part series of blog posts.

  1. Modern Web Application Layered High Level Architecture with SPA, MVC, Web API, EF, Kendo UI, OData
  2. Generically Implementing the Unit of Work & Repository Pattern with Entity Framework in MVC & Simplifying Entity Graphs
  3. MVC 4, Kendo UI, SPA with Layout, View, Router & MVVM
  4. MVC 4, Web API, OData, EF, Kendo UI, Grid, Datasource (CRUD) with MVVM
  5. MVC 4, Web API, OData, EF, Kendo UI, Binding a Form to Datasource (CRUD) with MVVM
  6. Upgrading to Async with Entity Framework, MVC, OData AsyncEntitySetController, Kendo UI, Glimpse & Generic Unit of Work Repository Framework v2.0

We’ll continue on from the most recent post in this series, you can do a quick review of it here http://blog.longle.net/2013/06/19/mvc-4-web-api-odata-ef-kendo-ui-binding-a-form-to-datasource-crud-with-mvvm-part. Now let’s get right into it, by first taking a look at what was all involved on the server side.

First off let’s take a quick look and the changes we made to our DbContextBase to support Async.

Repository.DbContextBase.cs

Before


    public class DbContextBase : DbContext, IDbContext
    {
        private readonly Guid _instanceId;

        public DbContextBase(string nameOrConnectionString) : base(nameOrConnectionString)
        {
            _instanceId = Guid.NewGuid();
        }

        public Guid InstanceId
        {
            get { return _instanceId; }
        }

        public void ApplyStateChanges()
        {
            foreach (var dbEntityEntry in ChangeTracker.Entries())
            {
                var entityState = dbEntityEntry.Entity as IObjectState;
                if (entityState == null)
                    throw new InvalidCastException("All entites must implement the IObjectState interface, " +
                                                   "this interface must be implemented so each entites state can explicitely determined when updating graphs.");

                dbEntityEntry.State = StateHelper.ConvertState(entityState.State);
            }
        }

        public new IDbSet<T> Set<T>() where T : class
        {
            return base.Set<T>();
        }

        protected override void OnModelCreating(DbModelBuilder builder)
        {
            builder.Conventions.Remove<PluralizingTableNameConvention>();
            base.OnModelCreating(builder);
        }

        public override int SaveChanges()
        {
            ApplyStateChanges();
            return base.SaveChanges();
        }
    }

After:


    public class DbContextBase : DbContext, IDbContext
    {
        private readonly Guid _instanceId;

        public DbContextBase(string nameOrConnectionString) : base(nameOrConnectionString)
        {
            _instanceId = Guid.NewGuid();
        }

        public Guid InstanceId
        {
            get { return _instanceId; }
        }

        public void ApplyStateChanges()
        {
            foreach (DbEntityEntry dbEntityEntry in ChangeTracker.Entries())
            {
                var entityState = dbEntityEntry.Entity as IObjectState;
                if (entityState == null)
                    throw new InvalidCastException("All entites must implement the IObjectState interface, " +
                                                   "this interface must be implemented so each entites state can explicitely determined when updating graphs.");

                dbEntityEntry.State = StateHelper.ConvertState(entityState.State);
            }
        }

        public new IDbSet<T> Set<T>() where T : class
        {
            return base.Set<T>();
        }

        public override int SaveChanges()
        {
            ApplyStateChanges();
            return base.SaveChanges();
        }

        public override Task<int> SaveChangesAsync()
        {
            ApplyStateChanges();
            return base.SaveChangesAsync();
        }

        public override Task<int> SaveChangesAsync(CancellationToken cancellationToken)
        {
            ApplyStateChanges();
            return base.SaveChangesAsync(cancellationToken);
        }

        protected override void OnModelCreating(DbModelBuilder builder)
        {
            builder.Conventions.Remove<PluralizingTableNameConvention>();
            base.OnModelCreating(builder);
        }
    }

All that was needed here was to expose all the DbContext Async save operations so that we could use with our IUnitOfWork implementation, and also not forgetting to invoke our ApplyStateChanges so that we are managing the different states each entity could have when dealing with graphs.

Next up, are the enhancements made to our Repository.cs, so that our generic repositories can leverage the Async goodness as well.

Repostiory.Repository.cs

Before:


 public class Repository<TEntity> : IRepository<TEntity> where TEntity : class
    {
        private readonly Guid _instanceId;
        internal IDbContext Context;
        internal IDbSet<TEntity> DbSet;

        public Repository(IDbContext context)
        {
            Context = context;
            DbSet = context.Set<TEntity>();
            _instanceId = Guid.NewGuid();
        }

        public Guid InstanceId
        {
            get { return _instanceId; }
        }

        public virtual TEntity FindById(object id)
        {
            return DbSet.Find(id);
        }

        public virtual void InsertGraph(TEntity entity)
        {
            DbSet.Add(entity);
        }

        public virtual void Update(TEntity entity)
        {
            DbSet.Attach(entity);
        }

        public virtual void Delete(object id)
        {
            var entity = DbSet.Find(id);
            ((IObjectState) entity).State = ObjectState.Deleted;
            Delete(entity);
        }

        public virtual void Delete(TEntity entity)
        {
            DbSet.Attach(entity);
            DbSet.Remove(entity);
        }

        public virtual void Insert(TEntity entity)
        {
            DbSet.Attach(entity);
        }

        public virtual IRepositoryQuery<TEntity> Query()
        {
            var repositoryGetFluentHelper = new RepositoryQuery<TEntity>(this);
            return repositoryGetFluentHelper;
        }

        internal IQueryable<TEntity> Get(
            Expression<Func<TEntity, bool>> filter = null,
            Func<IQueryable<TEntity>, IOrderedQueryable<TEntity>> orderBy = null,
            List<Expression<Func<TEntity, object>>> includeProperties = null,
            int? page = null,
            int? pageSize = null)
        {
            IQueryable<TEntity> query = DbSet;

            if (includeProperties != null)
                includeProperties.ForEach(i => query = query.Include(i));

            if (filter != null)
                query = query.Where(filter);

            if (orderBy != null)
                query = orderBy(query);

            if (page != null && pageSize != null)
                query = query
                    .Skip((page.Value - 1)*pageSize.Value)
                    .Take(pageSize.Value);

            var results = query;

            return results;
        }
    }

After:


    public class Repository<TEntity> : IRepository<TEntity> where TEntity : class
    {
        private readonly Guid _instanceId;
        private readonly DbSet<TEntity> _dbSet;

        public Repository(IDbContext context)
        {
            _dbSet = context.Set<TEntity>();
            _instanceId = Guid.NewGuid();
        }

        public Guid InstanceId
        {
            get { return _instanceId; }
        }

        public virtual TEntity Find(params object[] keyValues)
        {
            return _dbSet.Find(keyValues);
        }

        public virtual async Task<TEntity> FindAsync(params object[] keyValues)
        {
            return await _dbSet.FindAsync(keyValues);
        }

        public virtual async Task<TEntity> FindAsync(CancellationToken cancellationToken, params object[] keyValues)
        {
            return await _dbSet.FindAsync(cancellationToken, keyValues);
        }

        public virtual IQueryable<TEntity> SqlQuery(string query, params object[] parameters)
        {
            return _dbSet.SqlQuery(query, parameters).AsQueryable();
        }

        public virtual void InsertGraph(TEntity entity)
        {
            _dbSet.Add(entity);
        }

        public virtual void Update(TEntity entity)
        {
            _dbSet.Attach(entity);
            ((IObjectState)entity).State = ObjectState.Modified;
        }

        public virtual void Delete(object id)
        {
            var entity = _dbSet.Find(id);
            Delete(entity);
        }

        public virtual void Delete(TEntity entity)
        {
            _dbSet.Attach(entity);
            ((IObjectState)entity).State = ObjectState.Deleted;
            _dbSet.Remove(entity);
        }

        public virtual void Insert(TEntity entity)
        {
            _dbSet.Attach(entity);
            ((IObjectState)entity).State = ObjectState.Added;
        }

        public virtual IRepositoryQuery<TEntity> Query()
        {
            var repositoryGetFluentHelper = new RepositoryQuery<TEntity>(this);
            return repositoryGetFluentHelper;
        }

        internal IQueryable<TEntity> Get(
            Expression<Func<TEntity, bool>> filter = null,
            Func<IQueryable<TEntity>, IOrderedQueryable<TEntity>> orderBy = null,
            List<Expression<Func<TEntity, object>>> includeProperties = null,
            int? page = null,
            int? pageSize = null)
        {
            IQueryable<TEntity> query = _dbSet;

            if (includeProperties != null)
            {
                includeProperties.ForEach(i => query = query.Include(i));
            }

            if (filter != null)
            {
                query = query.Where(filter);
            }

            if (orderBy != null)
            {
                query = orderBy(query);
            }

            if (page != null && pageSize != null)
            {
                query = query
                    .Skip((page.Value - 1)*pageSize.Value)
                    .Take(pageSize.Value);
            }
            return query;
        }

        internal async Task<IEnumerable<TEntity>> GetAsync(
                    Expression<Func<TEntity, bool>> filter = null,
                    Func<IQueryable<TEntity>, IOrderedQueryable<TEntity>> orderBy = null,
                    List<Expression<Func<TEntity, object>>> includeProperties = null,
                    int? page = null,
                    int? pageSize = null)
        {
            return Get(filter, orderBy, includeProperties, page, pageSize).AsEnumerable();
        }
    }

Here we’ve exposed the FindAsync methods from DbSet, so our Repositories can make use of them, and we’ve also wrapped implemented an Async implementation of our Get() method so that we can use it in our new Web Api ProductController.cs later.

Important note: here is that although our method is named GetAsync, it is not truly performing an Async interaction, this is due to the fact that if we were to use ToListAsync(), we would already executed the the query prior to OData applying it’s criteria to the execution plan e.g. if the OData query was requesting 10 records for page 2 of a grid from a Products table that had 1000 rows in it, ToListAsync() would have actually pulled a 1000 records from SQL to the web server and at that time do a skip 10 and take 20 from the collection of Products with 1000 objects. What we want is for this to happen on the SQL Server, meaning, SQL query the Products table, skip the first 10, and take next 10 records and only send those 10 records over to the web server, which will eventually surface into the Grid in the user’s browsers. Hence we are favoring payload size (true SQL Server side paging) going over the wire, vs. a true Async call to SQL.

Northwind.Web.Areas.Spa.Api.ProductController.cs

Before:


    public class ProductController : EntitySetController<Product, int>
    {
        private readonly IUnitOfWork _unitOfWork;

        public ProductController(IUnitOfWork unitOfWork)
        {
            _unitOfWork = unitOfWork;
        }

        public override IQueryable<Product> Get()
        {
            return _unitOfWork.Repository<Product>().Query().Get();
        }

        protected override Product GetEntityByKey(int key)
        {
            return _unitOfWork.Repository<Product>().FindById(key);
        }

        protected override Product UpdateEntity(int key, Product update)
        {
            update.State = ObjectState.Modified;
            _unitOfWork.Repository<Product>().Update(update);
            _unitOfWork.Save();

            return update;
        }

        public override void Delete([FromODataUri] int key)
        {
            _unitOfWork.Repository<Product>().Delete(key);
            _unitOfWork.Save();
        }

        protected override void Dispose(bool disposing)
        {
            _unitOfWork.Dispose();
            base.Dispose(disposing);
        }
    }
 

After:

Note: Don’t be overwhelmed by how much more code there is in the “After” for our new ProductController that now inherits AsyncEntitySetController. I’ll explain later, what all the other Actions are there for. For now, please keep in mind there are only a few of these Actions that are actually required for the use case on the live demo site. The only Actions (methods) that are needed for our use case are as follows:

  • Task<IEnumerable> Get()
  • Task Get([FromODataUri] int key)
  • Task UpdateEntityAsync(int key, Product update)
  • Task Delete([FromODataUri] int key)

[ODataNullValue]
public class ProductController : AsyncEntitySetController&lt;Product, int&gt;
{
    private readonly IUnitOfWork _unitOfWork;

    public ProductController(IUnitOfWork unitOfWork)
    {
        _unitOfWork = unitOfWork;
    }

    protected override void Dispose(bool disposing)
    {
        _unitOfWork.Dispose();
        base.Dispose(disposing);
    }

    protected override int GetKey(Product entity)
    {
        return entity.ProductID;
    }

[Queryable]
public override async Task&lt;IEnumerable&lt;Product&gt;&gt; Get()
{
return await _unitOfWork.Repository&lt;Product&gt;().Query().GetAsync();
}

    [Queryable]
    public override async Task&lt;HttpResponseMessage&gt; Get([FromODataUri] int key)
    {
        var query = _unitOfWork.Repository&lt;Product&gt;().Query().Filter(x =&gt; x.ProductID == key).Get();
        return Request.CreateResponse(HttpStatusCode.OK, query);
    }

    ///// &lt;summary&gt;
    ///// Retrieve an entity by key from the entity set.
    ///// &lt;/summary&gt;
    ///// &lt;param name=&quot;key&quot;&gt;The entity key of the entity to retrieve.&lt;/param&gt;
    ///// &lt;returns&gt;A Task that contains the retrieved entity when it completes, or null if an entity with the specified entity key cannot be found in the entity set.&lt;/returns&gt;
    [Queryable]
    protected override async Task&lt;Product&gt; GetEntityByKeyAsync(int key)
    {
        return await _unitOfWork.Repository&lt;Product&gt;().FindAsync(key);
    }

    protected override async Task&lt;Product&gt; CreateEntityAsync(Product entity)
    {
        if (entity == null)
            throw new HttpResponseException(HttpStatusCode.BadRequest);
            
        _unitOfWork.Repository&lt;Product&gt;().Insert(entity);
        await _unitOfWork.SaveAsync();
        return entity;
    }

    protected override async Task&lt;Product&gt; UpdateEntityAsync(int key, Product update)
    {
        if (update == null)
            throw new HttpResponseException(HttpStatusCode.BadRequest);
            
        if (key != update.ProductID)
            throw new HttpResponseException(Request.CreateODataErrorResponse(HttpStatusCode.BadRequest, new ODataError { Message = &quot;The supplied key and the Product being updated do not match.&quot; }));

        try
        {
            update.State = ObjectState.Modified;
            _unitOfWork.Repository&lt;Product&gt;().Update(update);
            var x = await _unitOfWork.SaveAsync();
        }
        catch (DbUpdateConcurrencyException)
        {
            throw new HttpResponseException(HttpStatusCode.BadRequest);
        }
        return update;
    }

    // PATCH &lt;controller&gt;(key)
    /// &lt;summary&gt;
    /// Apply a partial update to an existing entity in the entity set.
    /// &lt;/summary&gt;
    /// &lt;param name=&quot;key&quot;&gt;The entity key of the entity to update.&lt;/param&gt;
    /// &lt;param name=&quot;patch&quot;&gt;The patch representing the partial update.&lt;/param&gt;
    /// &lt;returns&gt;A Task that contains the updated entity when it completes.&lt;/returns&gt;
    protected override async Task&lt;Product&gt; PatchEntityAsync(int key, Delta&lt;Product&gt; patch)
    {
        if (patch == null)
            throw new HttpResponseException(HttpStatusCode.BadRequest);

        if (key != patch.GetEntity().ProductID)
            throw Request.EntityNotFound();

        var entity = await _unitOfWork.Repository&lt;Product&gt;().FindAsync(key);

        if (entity == null)
            throw Request.EntityNotFound();

        try
        {
            patch.Patch(entity);
            await _unitOfWork.SaveAsync();
        }
        catch (DbUpdateConcurrencyException)
        {
            throw new HttpResponseException(HttpStatusCode.Conflict);
        }
        return entity;
    }

    public override async Task Delete([FromODataUri] int key)
    {
        var entity = await _unitOfWork.Repository&lt;Product&gt;().FindAsync(key);

        if (entity == null)
            throw Request.EntityNotFound();

        _unitOfWork.Repository&lt;Product&gt;().Delete(entity);

        try
        {
            await _unitOfWork.SaveAsync();
        }
        catch (Exception e)
        { 
            throw new HttpResponseException(
                new HttpResponseMessage(HttpStatusCode.Conflict)
                {
                    StatusCode = HttpStatusCode.Conflict, 
                    Content = new StringContent(e.Message), 
                    ReasonPhrase = e.InnerException.InnerException.Message
                });
        }
    }

    #region Links
    // Create a relation from Product to Category or Supplier, by creating a $link entity.
    // POST &lt;controller&gt;(key)/$links/Category
    // POST &lt;controller&gt;(key)/$links/Supplier
    /// &lt;summary&gt;
    /// Handle POST and PUT requests that attempt to create a link between two entities.
    /// &lt;/summary&gt;
    /// &lt;param name=&quot;key&quot;&gt;The key of the entity with the navigation property.&lt;/param&gt;
    /// &lt;param name=&quot;navigationProperty&quot;&gt;The name of the navigation property.&lt;/param&gt;
    /// &lt;param name=&quot;link&quot;&gt;The URI of the entity to link.&lt;/param&gt;
    /// &lt;returns&gt;A Task that completes when the link has been successfully created.&lt;/returns&gt;
    [AcceptVerbs(&quot;POST&quot;, &quot;PUT&quot;)]
    public override async Task CreateLink([FromODataUri] int key, string navigationProperty, [FromBody] Uri link)
    {
        var entity = await _unitOfWork.Repository&lt;Product&gt;().FindAsync(key);

        if (entity == null)
            throw Request.EntityNotFound();
            
        switch (navigationProperty)
        {
            case &quot;Category&quot;:
                var categoryKey = Request.GetKeyValue&lt;int&gt;(link);
                var category = await _unitOfWork.Repository&lt;Category&gt;().FindAsync(categoryKey);

                if (category == null)
                    throw Request.EntityNotFound();
                    
                    entity.Category = category;
                break;

            case &quot;Supplier&quot;:
                var supplierKey = Request.GetKeyValue&lt;int&gt;(link);
                var supplier = await _unitOfWork.Repository&lt;Supplier&gt;().FindAsync(supplierKey);

                if (supplier == null)
                    throw Request.EntityNotFound();
                    
                    entity.Supplier = supplier;
                break;

            default:
                await base.CreateLink(key, navigationProperty, link);
                break;
        }
        await _unitOfWork.SaveAsync();
    }

    // Remove a relation, by deleting a $link entity
    // DELETE &lt;controller&gt;(key)/$links/Category
    // DELETE &lt;controller&gt;(key)/$links/Supplier
    /// &lt;summary&gt;
    /// Handle DELETE requests that attempt to break a relationship between two entities.
    /// &lt;/summary&gt;
    /// &lt;param name=&quot;key&quot;&gt;The key of the entity with the navigation property.&lt;/param&gt;
    /// &lt;param name=&quot;relatedKey&quot;&gt;The key of the related entity.&lt;/param&gt;
    /// &lt;param name=&quot;navigationProperty&quot;&gt;The name of the navigation property.&lt;/param&gt;
    /// &lt;returns&gt;Task.&lt;/returns&gt;
    public override async Task DeleteLink([FromODataUri] int key, string relatedKey, string navigationProperty)
    {
        var entity = await _unitOfWork.Repository&lt;Product&gt;().FindAsync(key);

        if (entity == null)
            throw Request.EntityNotFound();

        switch (navigationProperty)
        {
            case &quot;Category&quot;:
                entity.Category = null;
                break;

            case &quot;Supplier&quot;:
                entity.Supplier = null;
                break;

            default:
                await base.DeleteLink(key, relatedKey, navigationProperty);
                break;
        }

        await _unitOfWork.SaveAsync();
    }

    // Remove a relation, by deleting a $link entity
    // DELETE &lt;controller&gt;(key)/$links/Category
    // DELETE &lt;controller&gt;(key)/$links/Supplier
    /// &lt;summary&gt;
    /// Handle DELETE requests that attempt to break a relationship between two entities.
    /// &lt;/summary&gt;
    /// &lt;param name=&quot;key&quot;&gt;The key of the entity with the navigation property.&lt;/param&gt;
    /// &lt;param name=&quot;navigationProperty&quot;&gt;The name of the navigation property.&lt;/param&gt;
    /// &lt;param name=&quot;link&quot;&gt;The URI of the entity to remove from the navigation property.&lt;/param&gt;
    /// &lt;returns&gt;Task.&lt;/returns&gt;
    public override async Task DeleteLink([FromODataUri] int key, string navigationProperty, [FromBody] Uri link)
    {
        var entity = await _unitOfWork.Repository&lt;Product&gt;().FindAsync(key);

        if (entity == null)
            throw Request.EntityNotFound();

        switch (navigationProperty)
        {
            case &quot;Category&quot;:
                entity.Category = null;
                break;

            case &quot;Supplier&quot;:
                entity.Supplier = null;
                break;

            default:
                await base.DeleteLink(key, navigationProperty, link);
                break;
        }

        await _unitOfWork.SaveAsync();
    }
    #endregion Links

    public override async Task&lt;HttpResponseMessage&gt; HandleUnmappedRequest(ODataPath odataPath)
    {
        //TODO: add logic and proper return values
        return Request.CreateResponse(HttpStatusCode.NoContent, odataPath);
    }

    #region Navigation Properties
    public async Task&lt;Category&gt; GetCategory(int key)
    {
        var entity = await _unitOfWork.Repository&lt;Product&gt;().FindAsync(key);

        if (entity == null)
            throw Request.EntityNotFound();
            
        return entity.Category;
    }

    public async Task&lt;Supplier&gt; GetSupplier(int key)
    {
        var entity = await _unitOfWork.Repository&lt;Product&gt;().FindAsync(key);

        if (entity == null)
            throw Request.EntityNotFound();
            
        return entity.Supplier;
    }
    #endregion Navigation Properties
}

Quickly looking at this, one can realize there is a lot more code than our pre-Async implementation. Well don’t be alarmed, there’s a lot of code here that wasn’t required to support our use case in the live demo (http://longle.azurewebsites.net), however we wanted to take the extra step so that we can really grasp on how to work with entity graphs with OData by leveraging the ?$expand query string parameter.

We’ll leave all the other that Actions that aren’t actually required for our use case on the live demo SPA as is, so we can see how to deep load your entity graph with OData and Web Api. We’ve included some pre-baked clickable OData URL’s (queries) on the View so that you can actually click and see the response payload in your browser (you’ll have to use Chrome or Firefox, IE has some catching up to do here).

*Click on image
10-9-2013 8-51-43 PM

Now let’s do a deep dive on the our Async Get() Action in our Controller.


[Queryable]
 
public override async Task&lt;IEnumerable&lt;Product&gt;&gt; Get()
{
    return await _unitOfWork.Repository&lt;Product&gt;().Query().GetAsync();
}
 

My initial thought when seeing this this Action (signature) is that it’s not IQueryable?! Which means that the SQL plan from EF has already been executed before OData has an opportunity to apply it’s criteria to the query plan! Well that’s not the case, we outfitted the Project with Glimpse and Glimpse EF6 to actually see what SQL queries were being sent over the wire.

So let’s take a look at the loading up our Kendo UI Grid with the awesomeness of Glimpse running. Since our View is built with Kendo UI, and we know it’s invoking Ajax calls to request data, we’ll click on the Ajax panel on the Glimpse HUD.

*Click on image
10-9-2013 7-30-56 PM

Now with the HUD automatically switching to standard view we can see all the Ajax requests that our View made, we are interested in the OData request that was made to hydrate our Kendo Grid.

*Click on image
10-9-2013 8-04-32 PM

After clicking on Inspect for the Ajax OData request, we see that menu buttons buttons that have tracing data for that request start to actual blink…! One of them being SQL, so let’s click on it.

*Click on image
10-9-2013 8-32-10 PM

Ladies and gentlemen, I kid you not, behold this is the actual SQL query that was from our Unit Of Work -> Repostiory -> Entity Framework 6 -> T-SQL, that was actually sent to SQL Server (actually in our case SQL Server CE, so that the live demo can be complete free with Azure Website without the need to pay for SQL Azure). BTW, we just scratching the surface of what Glimpse can do, the list is pretty much endless e.g. displays MVC Routes, Actions, Tracing, Environment Variables, MVC Views, and performance metrics for pretty much all of them, etc.

Now back to the topic at hand, we can definitively see that although our Action and our Repository are returning IEnumerable:

Get Action the Kendo UI Datasource is calling, which returns IEnumerable.


[Queryable] 
 
public override async Task&lt;IEnumerable&lt;Product&gt;&gt; Get()
{
    return await _unitOfWork.Repository&lt;Product&gt;().Query().GetAsync();
}
 

Repository method the Action is calling, which also returns IEnumerable.


        internal async Task&lt;IEnumerable&lt;TEntity&gt;&gt; GetAsync(
                    Expression&lt;Func&lt;TEntity, bool&gt;&gt; filter = null,
                    Func&lt;IQueryable&lt;TEntity&gt;, IOrderedQueryable&lt;TEntity&gt;&gt; orderBy = null,
                    List&lt;Expression&lt;Func&lt;TEntity, object&gt;&gt;&gt; includeProperties = null,
                    int? page = null,
                    int? pageSize = null)
        {
            return Get(filter, orderBy, includeProperties, page, pageSize).AsEnumerable();
        }
 

The query plan is still valid, meaning it’s selecting only the rows (10 records to be exact) that the Grid is requesting for page one (1) of the Grid. So how is this happening? Well we’ve decorated our action with the [Queryable] attribute, so OData and Web Api is able to perform it’s magic together during run-time in the ASP.NET HTTP pipeline.

T-SQL that’s being sent over the wire, courtesy of Glimpse EF6

 
 
SELECT TOP (10 /* @p__linq__0 */) 
    [Extent1].[Product ID] AS [Product ID], 
    [Extent1].[Product Name] AS [Product Name], 
    [Extent1].[Supplier ID] AS [Supplier ID], 
    [Extent1].[Category ID] AS [Category ID], 
    [Extent1].[Quantity Per Unit] AS [Quantity Per Unit], 
    [Extent1].[Unit Price] AS [Unit Price], 
    [Extent1].[Units In Stock] AS [Units In Stock], 
    [Extent1].[Units On Order] AS [Units On Order], 
    [Extent1].[Reorder Level] AS [Reorder Level], 
    [Extent1].[Discontinued] AS [Discontinued]
    FROM [Products] AS [Extent1]
    ORDER BY [Extent1].[Product ID] ASC
 

Now, let’s cover at a high-level on all the Actions that aren’t required for our live demo use case, which are mostly to support Navigation Properties e.g. Product.Supplier, Product.Category, etc.

The $expand query string parameter allows us to hydrate complex navigation property types. For example in our case when we query for a Product, and Product has a property of Category and we the Category to be hydrated with its data we would leverage the $expand querystring parameter to do this, click this Url : http://longle.azurewebsites.net/odata/Product/?$inlinecount=allpages&$orderby=ProductName&$skip=1&$top=2&$expand=Category&$select=ProductID,ProductName,Category/CategoryID,Category/CategoryName to see the $expand in action.

T-SQL that’s being sent over the wire, again, courtesy of Glimpse EF6

 
 
SELECT TOP (2 /* @p__linq__1 */) 
    [top].[Product ID] AS [Product ID], 
    [top].[C1] AS [C1], 
    [top].[C2] AS [C2], 
    [top].[Product Name] AS [Product Name], 
    [top].[C3] AS [C3], 
    [top].[C4] AS [C4], 
    [top].[C5] AS [C5], 
    [top].[C6] AS [C6], 
    [top].[Category Name] AS [Category Name], 
    [top].[C7] AS [C7], 
    [top].[Category ID] AS [Category ID], 
    [top].[C8] AS [C8]
    FROM ( SELECT [Project1].[Product ID] AS [Product ID], [Project1].[Product Name] AS [Product Name], [Project1].[Category ID] AS [Category ID], [Project1].[Category Name] AS [Category Name], [Project1].[C1] AS [C1], [Project1].[C2] AS [C2], [Project1].[C3] AS [C3], [Project1].[C4] AS [C4], [Project1].[C5] AS [C5], [Project1].[C6] AS [C6], [Project1].[C7] AS [C7], [Project1].[C8] AS [C8]
        FROM ( SELECT 
            [Extent1].[Product ID] AS [Product ID], 
            [Extent1].[Product Name] AS [Product Name], 
            [Extent1].[Category ID] AS [Category ID], 
            [Extent2].[Category Name] AS [Category Name], 
            N'ace5ad31-e3e9-4cde-9bb8-d75fced846fa' AS [C1], 
            N'ProductName' AS [C2], 
            N'ProductID' AS [C3], 
            N'Category' AS [C4], 
            N'ace5ad31-e3e9-4cde-9bb8-d75fced846fa' AS [C5], 
            N'CategoryName' AS [C6], 
            N'CategoryID' AS [C7], 
            CASE WHEN ([Extent1].[Category ID] IS NULL) THEN cast(1 as bit) ELSE cast(0 as bit) END AS [C8]
            FROM  [Products] AS [Extent1]
            LEFT OUTER JOIN [Categories] AS [Extent2] ON [Extent1].[Category ID] = [Extent2].[Category ID]
        )  AS [Project1]
        ORDER BY [Project1].[Product Name] ASC, [Project1].[Product ID] ASC
        OFFSET 1 /* @p__linq__0 */ ROWS 
    )  AS [top]
 

Product results with Categories hydrated

 
  
{
  &quot;odata.metadata&quot;:&quot;http://longle.azurewebsites.net/odata/$metadata#Product&amp;$select=ProductID,ProductName,Category/CategoryID,Category/CategoryName&quot;,&quot;odata.count&quot;:&quot;77&quot;,&quot;value&quot;:[
    {
      &quot;Category&quot;:{
        &quot;CategoryID&quot;:2,&quot;CategoryName&quot;:&quot;Condiments&quot;
      },&quot;ProductID&quot;:3,&quot;ProductName&quot;:&quot;Aniseed Syrup&quot;
    },{
      &quot;Category&quot;:{
        &quot;CategoryID&quot;:8,&quot;CategoryName&quot;:&quot;Seafood&quot;
      },&quot;ProductID&quot;:40,&quot;ProductName&quot;:&quot;Boston Crab Meat&quot;
    }
  ]
} 
 

We can really see the power of Web Api and OData now, we’re actually able to query for Products (skip the first and take the next two) and request that Category be hydrated but specifically only the CategoryId and Name and none of the other fields.

Sample Application Client Side (Kendo UI) Tweaks

We’ve polished the UI/UX a bit, relocated Edit, Edit Details, and Delete buttons out of the rows into the Grid Toolbar (header) to make better use of the Grid real estate, using Kendo’s Template Framework, which illustrates how flexible Kendo UI can be. The app has been upgraded to, Twitter Bootstrap as by leveraging the new out of the box MVC Project Templates in Visual Studio 2013 (Preview) and changing the Kendo UI theme to Bootstrap to match.

All Kendo Views which are remotely loaded on demand into the SPA are now actually MVC Razor Views, the Kendo Router remotely loads views by traditional MVC routes e.g.
{controller}/{action}/{id} vs. what was in the previous post (http://blog.longle.net/2013/06/17/mvc-4-kendo-ui-spa-with-layout-router-mvvm/) which was just serving up raw *.html pages. This has been a request for devs that are making the transition from server side MVC development into the SPA realm, and had .NET libraries they still wanted to make use of and leverage in their their Controllers, and Razor Views for SPA’s. Obviously, all Views and ViewModel binding on the client-side are done with with Kendo’s MVVM Framework.

Northwind.Web/Areas/Spa/Content/Views/products.html

Before (non Razor, just plain *.html pages were used for SPA):

 
@{
    ViewBag.Title = &quot;Products&quot;;
    Layout = &quot;&quot;;
}
&lt;div class=&quot;row&quot;&gt;
    &lt;div class=&quot;span5&quot;&gt;
        &lt;h2&gt;Technlogy Stack&lt;/h2&gt;
        &lt;h3&gt;&lt;a href=&quot;http://blog.longle.net&quot;&gt;blog.longle.net&lt;/a&gt;&lt;/h3&gt;
        &lt;p&gt;ASP.NET MVC 4, Web API, OData, Entity Framework 6 CTP, EntityFramework CE 6 RC1, Visual Studio 2013 Preview, Sql Server CE, Twitter Bootstrap, Kendo UI Web, Azure Website PaaS (&lt;a href=&quot;http://www.windowsazure.com/en-us/develop/net/aspnet/&quot; target=&quot;blank&quot;&gt;free!&lt;/a&gt;)&lt;/p&gt;
        &lt;br /&gt;
        &lt;p&gt;&lt;a class=&quot;btn&quot; href=&quot;http://go.microsoft.com/fwlink/?LinkId=301865&quot;&gt;Learn more &amp;raquo;&lt;/a&gt;&lt;/p&gt;
    &lt;/div&gt;
&lt;/div&gt;

&lt;br /&gt;&lt;br /&gt;
&lt;div class=&quot;k-content&quot; style=&quot;width: 100%&quot;&gt;
    &lt;div id=&quot;view&quot;&gt;
        &lt;div id=&quot;productGrid&quot;
             data-role=&quot;grid&quot;
             data-sortable=&quot;true&quot;
             data-pageable=&quot;true&quot;
             data-filterable=&quot;true&quot;
             data-bind=&quot;source: dataSource, events: { dataBound: dataBound, change: onChange }&quot;
             data-editable=&quot;inline&quot;
             data-selectable=&quot;true&quot;
             data-toolbar='[ { template: $(&quot;#toolbar&quot;).html() } ]'
             data-columns='[
                    { field: &quot;ProductID&quot;, title: &quot;ID&quot;, width: &quot;50px&quot; },
                    { field: &quot;ProductName&quot;, title: &quot;Name&quot;},
                    { field: &quot;QuantityPerUnit&quot;, title: &quot;Quantity&quot;, width: &quot;200px&quot; },
                    { field: &quot;UnitsInStock&quot;, title: &quot;Stock&quot;, width: &quot;90px&quot; },
                    { field: &quot;UnitPrice&quot;, title: &quot;Price&quot;, format: &quot;{0:c}&quot;, width: &quot;100px&quot; },
                    { field: &quot;Discontinued&quot;, width: &quot;150px&quot; } ]'&gt;
        &lt;/div&gt;
    &lt;/div&gt;
    &lt;h3&gt;Use Chrome or Firefox and click on OData (queries) Urls below for example results.&lt;/h3&gt;
    &lt;ul&gt;
        &lt;li&gt;&lt;a href=&quot;/odata/$metadata&quot;&gt;/odata/$metadata&lt;/a&gt;&lt;/li&gt;
        &lt;li&gt;&lt;a href=&quot;/odata/Product&quot;&gt;/odata/Product&lt;/a&gt;&lt;/li&gt;
        &lt;li&gt;&lt;a href=&quot;/odata/Product/?$select=ProductID,ProductName&quot;&gt;/odata/Product/?$select=ProductID,ProductName&lt;/a&gt;&lt;/li&gt;
        &lt;li&gt;&lt;a href=&quot;/odata/Product/?$orderby=ProductName&amp;$skip=1&amp;$top=2&quot;&gt;/odata/Product/?$orderby=ProductName&amp;$skip=1&amp;$top=2&lt;/a&gt;&lt;/li&gt;
        &lt;li&gt;&lt;a href=&quot;/odata/Product/?$orderby=ProductName&amp;$skip=1&amp;$top=2&quot;&gt;/odata/Product/?$orderby=ProductName&amp;$skip=1&amp;$top=2&lt;/a&gt;&lt;/li&gt;
        &lt;li&gt;&lt;a href=&quot;/odata/Product/?$inlinecount=allpages&amp;$filter=UnitPrice ge 20&quot;&gt;/odata/Product/?$inlinecount=allpages&amp;$filter=UnitPrice ge 20&lt;/a&gt;&lt;/li&gt;
        &lt;li&gt;&lt;a href=&quot;/odata/Product/?$expand=Category&quot;&gt;/odata/Product/?$expand=Category&lt;/a&gt;&lt;/li&gt;
        &lt;li&gt;&lt;a href=&quot;/odata/Product/?$expand=Category&amp;$select=ProductID,ProductName,Category/CategoryID,Category/CategoryName&quot;&gt;/odata/Product/?$expand=Category&amp;$select=ProductID,ProductName,Category/CategoryID,Category/CategoryName&lt;/a&gt;&lt;/li&gt;
        &lt;li&gt;&lt;a href=&quot;/odata/Product/?$inlinecount=allpages&amp;$orderby=ProductName&amp;$skip=1&amp;$top=2&amp;$expand=Category&amp;$select=ProductID,ProductName,Category/CategoryID,Category/CategoryName&quot;&gt;/odata/Product/?$inlinecount=allpages&amp;$orderby=ProductName&amp;$skip=1&amp;$top=2&amp;$expand=Category&amp;$select=ProductID,ProductName,Category/CategoryID,Category/CategoryName&lt;/a&gt;&lt;/li&gt;
    &lt;/ul&gt;
&lt;/div&gt;

&lt;script type=&quot;text/x-kendo-template&quot; id=&quot;toolbar&quot;&gt;
    &lt;div class=&quot;toolbar&quot;&gt;
        &lt;a class=&quot;k-button&quot; onclick=&quot;edit(event);&quot;&gt;&lt;span class=&quot;k-icon k-i-tick&quot;&gt;&lt;/span&gt;Edit&lt;/a&gt;
        &lt;a class=&quot;k-button&quot; onclick=&quot;destroy(event);&quot;&gt;&lt;span class=&quot;k-icon k-i-tick&quot;&gt;&lt;/span&gt;Delete&lt;/a&gt;
        &lt;a class=&quot;k-button&quot; onclick=&quot;details(event);&quot;&gt;&lt;span class=&quot;k-icon k-i-tick&quot;&gt;&lt;/span&gt;Edit Details&lt;/a&gt;
    &lt;/div&gt;
    &lt;div class=&quot;toolbar&quot; style=&quot;display:none&quot;&gt;
        &lt;a class=&quot;k-button&quot; onclick=&quot;save(event);&quot;&gt;&lt;span class=&quot;k-icon k-i-tick&quot;&gt;&lt;/span&gt;Save&lt;/a&gt;
        &lt;a class=&quot;k-button&quot; onclick=&quot;cancel(event);&quot;&gt;&lt;span class=&quot;k-icon k-i-tick&quot;&gt;&lt;/span&gt;Cancel&lt;/a&gt;
    &lt;/div&gt;
&lt;/script&gt;

&lt;script&gt;
    var lastSelectedDataItem;

    var save = function (event) {
        onClick(event, function (grid) {
            grid.saveRow();
            $(&quot;.toolbar&quot;).toggle();
        });
    };

    var cancel = function (event) {
        onClick(event, function (grid) {
            grid.cancelRow();
            $(&quot;.toolbar&quot;).toggle();
        });
    };

    var details = function (event) {
        onClick(event, function (grid, row, dataItem) {
            window.location.href = '#/edit/' + dataItem.ProductID;
        });
    };

    var edit = function (event) {
        onClick(event, function (grid, row) {
            grid.editRow(row);
            $(&quot;.toolbar&quot;).toggle();
        });
    };

    var destroy = function (event) {
        onClick(event, function (grid, row, dataItem) {
            grid.dataSource.remove(dataItem);
            grid.dataSource.sync();
        });
    };

    var onClick = function (event, delegate) {
        event.preventDefault();
        var grid = $(&quot;#productGrid&quot;).data(&quot;kendoGrid&quot;);
        var selectedRow = grid.select();
        var dataItem = grid.dataItem(selectedRow);
        if (selectedRow.length &gt; 0)
            delegate(grid, selectedRow, dataItem);
        else
            alert(&quot;Please select a row.&quot;);
    };

    var Product = kendo.data.Model.define({
        id: &quot;ProductID&quot;,
        fields: {
            ProductID: { type: &quot;number&quot;, editable: false, nullable: true },
            ProductName: { type: &quot;string&quot;, validation: { required: true } },
            QuantityPerUnit: { type: &quot;string&quot;, validation: { required: true } },
            UnitsInStock: { type: &quot;number&quot;, validation: { required: true } },
            UnitPrice: { type: &quot;number&quot;, validation: { required: true, min: 1 } },
            Discontinued: { type: &quot;boolean&quot; }
        }
    });

    var baseUrl = &quot;/odata/Product&quot;;

    var dataSource = new kendo.data.DataSource({
        type: &quot;odata&quot;,
        transport: {
            read: {
                url: baseUrl,
                dataType: &quot;json&quot;
            },
            update: {
                url: function (data) {
                    return baseUrl + &quot;(&quot; + data.ProductID + &quot;)&quot;;
                },
                dataType: &quot;json&quot;
            },
            destroy: {
                url: function (data) {
                    return baseUrl + &quot;(&quot; + data.ProductID + &quot;)&quot;;
                },
                dataType: &quot;json&quot;
            }
        },
        batch: false,
        serverPaging: true,
        serverSorting: true,
        serverFiltering: true,
        pageSize: 10,
        schema: {
            data: function (data) {
                return data.value;
            },
            total: function (data) {
                return data[&quot;odata.count&quot;];
            },
            errors: function (e) {
                return e.errors;
            },
            model: Product
        },
        error: function (e) {
            var responseJson = e.xhr.responseJSON;
            if (responseJson != undefined) {
                if (responseJson[&quot;odata.error&quot;] != undefined) {
                    var error = responseJson[&quot;odata.error&quot;];
                    var message = error.message.value + '\n\n' + error.innererror.message;
                    alert(message);
                }
            } else {
                alert(e.xhr.status + &quot;\n\n&quot; + e.xhr.responseText + &quot;\n\n&quot; + e.xhr.statusText);
            }
            this.read();
        }
    });

    var viewModel = kendo.observable({
        dataSource: dataSource,
        dataBound: function (arg) {
            if (lastSelectedDataItem == null) return; // check if there was a row that was selected
            var view = this.dataSource.view(); // get all the rows
            for (var i = 0; i &lt; view.length; i++) { // iterate through rows
                if (view[i].ProductID == lastSelectedDataItem.ProductID) { // find row with the lastSelectedProductd
                    var grid = arg.sender; // get the grid
                    grid.select(grid.table.find(&quot;tr[data-uid='&quot; + view[i].uid + &quot;']&quot;)); // set the selected row
                    break;
                }
            }
        },
        onChange: function (arg) {
            var grid = arg.sender;
            lastSelectedDataItem = grid.dataItem(grid.select());
        },
    });

    $(document).bind(&quot;viewSwtichedEvent&quot;, function (e, args) { // subscribe to the viewSwitchedEvent
        if (args.name == &quot;list&quot;) { // check if this view was switched too
            if (args.isRemotelyLoaded) { // check if this view was loaded for the first time (remotely from server)
                kendo.bind($(&quot;#view&quot;), viewModel); // bind the view to the model
            } else {// view already been loaded in cache
                viewModel.dataSource.read(); // refresh grid
            }
        }
    });

&lt;/script&gt;
&lt;style scoped&gt;
    #productGrid .k-toolbar {
        padding: .7em;
    }

    .toolbar {
        float: right;
    }
&lt;/style&gt;
 

10-9-2013 7-11-39 PM

Happy Coding…! :)

Live Demo: http://longle.azurewebsites.net
Download: https://genericunitofworkandrepositories.codeplex.com/

Modern Web Application Layered High Level Architecture with SPA, MVC, Web API, EF, Kendo UI, OData

This will be part one of a six part series of blog posts.

  1. Modern Web Application Layered High Level Architecture with SPA, MVC, Web API, EF, Kendo UI, OData
  2. Generically Implementing the Unit of Work & Repository Pattern with Entity Framework in MVC & Simplifying Entity Graphs
  3. MVC 4, Kendo UI, SPA with Layout, View, Router & MVVM
  4. MVC 4, Web API, OData, EF, Kendo UI, Grid, Datasource (CRUD) with MVVM
  5. MVC 4, Web API, OData, EF, Kendo UI, Binding a Form to Datasource (CRUD) with MVVM
  6. Upgrading to Async with Entity Framework, MVC, OData AsyncEntitySetController, Kendo UI, Glimpse & Generic Unit of Work Repository Framework v2.0

Update: 07/22/2013 – Added blog series on actual implementation steps, for this architecture with patterns towards the end of this blog post.

Search and searched and seems difficult to locate any comprehensive top down, full stack architecture or high level design diagrams for modern (SPA) web apps. It’s probably important you have at least a high level picture what this architecture looks like now that there is quite a bit more design work involved on the client side especially with more and more implementations are around SPA and patterns like MVVM; so hence this post. Obviously there is no such thing as one size fits all especially when it comes to architecture, so feel free to omit or add to the architecture based on your specific needs.

Modern Web Application Logical and Physical Architecture High Level Design with SPA

Client Layer (HTML5 Browser)
Model View ViewModel (MVVM) is a design pattern which helps developers separate the Model (the data) from the View (the UI). The View-Model part of MVVM is responsible for exposing the data objects from the Model in such a way that those objects are easily consumed in the View. Kendo MVVM is an implementation of the MVVM pattern which seamlessly integrates with the rest of the Kendo framework (widgets and DataSource).

Web Layer (Server)
Almost the entire ASP.NET MVC Web Layer can leverage the DI & IoC Pattern, you can read up on what the benefits are and how to do this download both a sample MVC app that uses MEF or Unity 3 from one of my previous post.

  • Presentation Layer
    For modern MVC web applications, the presentation layer (server-side) consists of a Controllers who’s only tasks are to render an HTML page, css, Javascript, HTML templates, images, etc. Very little server-side code, if any, is responsible for any UI rendering responsibilities. Once the page is rendered in the browser client-side components (the browser or user agent that executes scripts and displays the HTML). With client-side techniques such as AJAX and with rich client-side frameworks such as Kendo UI Web, it is possible to execute logic on the client, for nice fluid user experiences. Implementing a SPA, can greatly increase the user experience by, reducing or eliminating post backs and refreshes.

  • Business Layer
    When designing the business layer for your Web application, consider how to implement the business logic and long-running workflows. Using a separate business layer that implements the business logic and workflows can improve the maintainability and testability of your application, and allow you to centralize and reuse common business logic functions.

  • Data Layer
    Consider designing a data layer for your Web application that abstracts the logic necessary to access the database. This can be achieved with implementing the Repository pattern, the Repository pattern is often implemented with the Unit of Work pattern. Entity Framework already implements the Unit of Work Pattern with the DbContext, however you should always work an abstraction of this, you can read up on one of previous post on how to do this. Using a separate data layer makes the application easier to configure and maintain, and hides the details of the database from other layers of the application.

    Your business entities, usually shared between the layers of your application e.g. Business and Data Layer should be POCO entities. Entity Framework enables you to use custom data classes together with your data model without making any modifications to the data classes themselves. This means that you can use “plain-old” CLR objects (POCO), such as existing domain objects, with your data model. These POCO data classes (also known as persistence-ignorant objects), which are mapped to entities that are defined in a data model, support most of the same query, insert, update, and delete behaviors as entity types that are generated by the Entity Data Model tools.

Services Layer
Consider designing a separate service layer if you plan to deploy your business layer on a remote tier, or if you plan to expose your business logic using a Web service. Design the services to achieve maximum reusability by not assuming the specific details of clients that will use them, and avoid changes over time that might break the service interface for existing clients. Instead, implement versions of the interface to allow clients to connect to the appropriate version.

Download PNG Version
Download PDF Version

I’ve posted a three part blog series, that covers the actual implementation of most of this architecture and patterns used:

Part 1 – MVC 4, Kendo UI, SPA with Layout, View, Router & MVVM
Part 2 – MVC 4, Web API, OData, EF, Kendo UI, Grid, Datasource (CRUD) with MVVM
Part 3 – MVC 4, Web API, OData, EF, Kendo UI, Binding a Form to Datasource (CRUD) with MVVM

Happy Architecting…!

Generically Implementing the Unit of Work & Repository Pattern with Entity Framework in MVC & Simplifying Entity Graphs

Update: 02/24/2014 – v3.2 released, improved API and reusable queries with the variation of the Query Object Pattern. Breaking change: Framework now ships returning all things TEntity or IEnumberable for compartmentalization, you will need to change the Repository.cs (see below, what methods signatures to change) if IQueryable is preferred over IEnumerable, IEnumerable is preferred as a best practice (http://genericunitofworkandrepositories.codeplex.com/documentation).

Update [01/06/2014] Quick start online video: http://blog.longle.net/2014/01/06/unit-of-work-unity-3-quick-start-video/

1-3-2014 5-43-38 PM

Update [11/18/2013]: Added mocked DbContext and DbSet and example Unit Tests using the mocks, download: https://genericunitofworkandrepositories.codeplex.com

This will be part two of a six part series of blog posts.

  1. Modern Web Application Layered High Level Architecture with SPA, MVC, Web API, EF, Kendo UI, OData
  2. Generically Implementing the Unit of Work & Repository Pattern with Entity Framework in MVC & Simplifying Entity Graphs
  3. MVC 4, Kendo UI, SPA with Layout, View, Router & MVVM
  4. MVC 4, Web API, OData, EF, Kendo UI, Grid, Datasource (CRUD) with MVVM
  5. MVC 4, Web API, OData, EF, Kendo UI, Binding a Form to Datasource (CRUD) with MVVM
  6. Upgrading to Async with Entity Framework, MVC, OData AsyncEntitySetController, Kendo UI, Glimpse & Generic Unit of Work Repository Framework v2.0

Update: 09/18/2013 – Sample application and source code has been uploaded to CodePlex: https://genericunitofworkandrepositories.codeplex.com, updated project to VS2013, Twitter Bootstrap, MVC 5, EF6, Kendo UI Bootstrap theme, project redeployed to Windows Azure Website.

Update: 07/30/2013 – To see this implementation with DI & IoC with EntLib Unity v3.0, see post: Bounded DbContext with Generic Unit of Work, Generic Repositories, Entity Framework 6 & EntLib Unity 3.0 in MVC 4.

Update: 06/21/2013 – Bug fix: Issue with deleting objects by Id in Repository.Delete(object Id). Updated blog post, and sample solution and added live demo link.

Live demo: http://longle.azurewebsites.net

First off let’s elegantly setup our solution, and prep it for real world development. We have our solution broken up into four different projects, now let’s talk about the “why?”.

5-8-2013 9-08-17 PM

Data Project (Data Access Layer)

This is where all of our ORM tooling related objects reside. In our case the EF (Entity Framework 6.0 Alpha 3) DataContext, Mappings, Migrations, etc. This give is nice separation, control and isolation of where any persistence related objects live. If ever, one day we need to change the tool of choice, or even upgrade, there’s only one layer or project to do this in, the Data project.

5-8-2013 10-08-26 PM

Entities Project (Domain Layer)
The Entities project is where all of our POCO (Plan Old C# Objects) objects will live. POCO’s should be very ignorant objects that pretty much have nothing in them but the structure of your data. With that being said, typically anything outside our Repository layer e.g. presentation layer (MVC), services layer (will cover in next post) should be completely ignorant to any persistence tool or technology e.g. NHibernate, eXpressPersistent, OpenAccess, EF (our case), etc.

5-8-2013 10-09-31 PM

Repository (Layer)
This is where our UoW (Unit of Work) pattern will be implemented as well as our Repository implementation. Our UoW implementation will handle most of our usual CRUD activities.

Two important objectives we will try to with our UoW pattern implementation are:

  1. Abstract away the ORM tool, in our case EF.
  2. Ensuring that all interactions with the database are happening under one DbContext instance per page request.

Obviously there are many other benefits, such giving us the ability to implement different variations of our UoW, potentially wire up to different types of repositories. For purposes of this article, we’ll stake focus on our two primary objectives, and I’ll cover the other benefits in later posts.

Web Project (Presentation Layer)
This is our presentation layer, for the purposes of the blog, we will use MVC (ASP.NET MVC 4). Again, this project should not have any dependent code on EF assembly, therefore that should not be any references to the EF assembly, it should only reference our Repository project for data access.

Refactoring the NorthwindContext for an Abstracted and Cleaner Implementation

Now that we’ve gone over the solution and it’s projects, let’s do a little bit of refactoring and cleaning up with our EF code.

Data.NorthwindDataContext.cs

Before:


    public class NorthwindContext : DbContext
    {
        static NorthwindContext()
        {
            Database.SetInitializer<NorthwindContext>(null);
        }

        public NorthwindContext()
            : base("Name=NorthwindContext")
        {
        }

        public DbSet Category Categories { get; set; }
        public DbSet CustomerDemographic CustomerDemographics { get; set; }
        public DbSet Customer Customers { get; set; }
        public DbSet Employee Employees { get; set; }
        public DbSet OrderDetail Order_Details { get; set; }
        public DbSet Order Orders { get; set; }
        public DbSet Product Products { get; set; }
        public DbSet Region Regions { get; set; }
        public DbSet Shipper Shippers { get; set; }
        public DbSet Supplier Suppliers { get; set; }
        public DbSet Territory Territories { get; set; }
        public DbSet Invoice Invoices { get; set; }


        protected override void OnModelCreating(DbModelBuilder modelBuilder)
        {
            modelBuilder.Configurations.Add(new CategoryMap());
            modelBuilder.Configurations.Add(new CustomerDemographicMap());
            modelBuilder.Configurations.Add(new CustomerMap());
            modelBuilder.Configurations.Add(new EmployeeMap());
            modelBuilder.Configurations.Add(new Order_DetailMap());
            modelBuilder.Configurations.Add(new OrderMap());
            modelBuilder.Configurations.Add(new ProductMap());
            modelBuilder.Configurations.Add(new RegionMap());
            modelBuilder.Configurations.Add(new ShipperMap());
            modelBuilder.Configurations.Add(new SupplierMap());
            modelBuilder.Configurations.Add(new TerritoryMap());
            modelBuilder.Configurations.Add(new InvoiceMap());
        }
    }

After:

     public class NorthwindContext : DbContext, IDbContext
    {
        static NorthwindContext()
        {
            Database.SetInitializer<NorthwindContext>(null);
        }

        public NorthwindContext()
            : base("Name=NorthwindContext")
        {
        }

        public new IDbSet<T> Set<T>() where T : class
        {
            return base.Set<T>();
        }

        public override int SaveChanges()
        {
            this.ApplyStateChanges();
            return base.SaveChanges();
        }

        protected override void OnModelCreating(DbModelBuilder modelBuilder)
        {
            modelBuilder.Configurations.Add(new CategoryMap());
            modelBuilder.Configurations.Add(new CustomerDemographicMap());
            modelBuilder.Configurations.Add(new CustomerMap());
            modelBuilder.Configurations.Add(new EmployeeMap());
            modelBuilder.Configurations.Add(new Order_DetailMap());
            modelBuilder.Configurations.Add(new OrderMap());
            modelBuilder.Configurations.Add(new ProductMap());
            modelBuilder.Configurations.Add(new RegionMap());
            modelBuilder.Configurations.Add(new ShipperMap());
            modelBuilder.Configurations.Add(new SupplierMap());
            modelBuilder.Configurations.Add(new TerritoryMap());
            modelBuilder.Configurations.Add(new InvoiceMap());
        }
    }

We can see that our DbContext is now much cleaner, and that it implements IDbContext. IDbContext will be the abstraction we will be working with when interacting with it’s concrete implementation, NorthwindContext.

Best Practice, Coding Against Abstractions or Interfaces

Abstractions serve as a nice flexibility point later, allowing us to implement different variations of the abstraction (interface). This will be very useful later when we implement DI (Dependency Injection and IoC (Inverse of Control) patterns. Coding to an abstraction will also help us easily create unit test, allowing us to inject faked or mocked instances as well. If your a bit unclear on how this helps set stage for DI, IoC and Unit Testing, no worries, I’ll cover these topics in the next post.

Data.IDbContext.cs


namespace Data
{
    public interface IDbContext
    {
        IDbSet<T> Set<T>() where T : class;
        int SaveChanges();
        DbEntityEntry Entry(object o);
        void Dispose();
    }
}

Now, let’s take take a look at what’s all in our Repository project, where our generic extensible repositories will reside.

5-10-2013 7-02-10 PM

IUnitOfWork This is simply the contract or abstraction that we will be working with, when interacting with it’s concrete implementation which will be UnitOfWork object.

Repository.IUnitOfwork.cs



namespace Repository
{
    public interface IUnitOfWork
    {
        void Dispose();
        void Save();
        void Dispose(bool disposing);
        IRepository<T> Repository<T>() where T : class;
    }
}

Concrete Implementation of IUnitOfWork.cs


namespace Repository
{
    public class UnitOfWork : IUnitOfWork
    {
        private readonly IDbContext _context;

        private bool _disposed;
        private Hashtable _repositories;

        public UnitOfWork(IDbContext context)
        {
            _context = context;
        }

        public UnitOfWork()
        {
            _context = new NorthwindContext();
        }

        public void Dispose()
        {
            Dispose(true);
            GC.SuppressFinalize(this);
        }

        public void Save()
        {
            _context.SaveChanges();
        }

        public virtual void Dispose(bool disposing)
        {
            if (!_disposed)
                if (disposing)
                    _context.Dispose();

            _disposed = true;
        }

        public IRepository<T> Repository<T>() where T : class
        {
            if (_repositories == null)
                _repositories = new Hashtable();

            var type = typeof (T).Name;

            if (!_repositories.ContainsKey(type))
            {
                var repositoryType = typeof (Repository<>);

                var repositoryInstance = 
                    Activator.CreateInstance(repositoryType
                            .MakeGenericType(typeof (T)), _context);
                
                _repositories.Add(type, repositoryInstance);
            }

            return (IRepository<T>) _repositories[type];
        }
    }
}

Let’s take a look at our IRepository Repository() method here in our UnitOfWork implementation. Here we are storing all the activated instances of repositories for each and every requests. One there is a request for a given repository we will first check to see if our Hashtable (container to hold all of our activated repository instances) has been created, if not, will go ahead and create our container. Next, we’ll scan our container to see if the requested repository instance has already been created, if it has, then will return it, if it hasn’t, we will activate the requested repository instance, store it in our container, and then return it. If it helps, you can think of this as lazy loading our repository instances, meaning we are only creating repository instances on demand, this allows us to only create the repository instances needed for a given web request. Last but not least, notice here how we are following best practices mentioned earlier, we are not return the concrete implementation for the Repository, but the abstraction, IRepository.

Repository.IRepository.cs


namespace Repository
{
    public interface IRepository<TEntity> where TEntity : class
    {
        TEntity FindById(object id);
        void InsertGraph(TEntity entity);
        void Update(TEntity entity);
        void Delete(object id);
        void Delete(TEntity entity);
        void Insert(TEntity entity);
        RepositoryQuery<TEntity> Query();
    }
}


Repository.Repository.cs


    public class Repository<TEntity> : IRepository<TEntity> where TEntity : class
    {
        internal IDbContext Context;
        internal IDbSet<TEntity> DbSet;

        public Repository(IDbContext context)
        {
            Context = context;
            DbSet = context.Set<TEntity>();
        }

        public virtual TEntity FindById(object id)
        {
            return DbSet.Find(id);
        }

        public virtual void InsertGraph(TEntity entity)
        {
            DbSet.Add(entity);
        }

        public virtual void Update(TEntity entity)
        {
            DbSet.Attach(entity);
        }

        public virtual void Delete(object id)
        {
            var entity = DbSet.Find(id);
            var objectState = entity as IObjectState;
            if (objectState != null) 
                objectState.State = ObjectState.Deleted;
            Delete(entity);
        }

        public virtual void Delete(TEntity entity)
        {
            DbSet.Attach(entity);
            DbSet.Remove(entity);
        }

        public virtual void Insert(TEntity entity)
        {
            DbSet.Attach(entity);
        }

        public virtual RepositoryQuery<TEntity> Query()
        {
            var repositoryGetFluentHelper =
                new RepositoryQuery<TEntity>(this);

            return repositoryGetFluentHelper;
        }

        internal IQueryable<TEntity> Get(
            Expression<Func<TEntity, bool>> filter = null,
            Func<IQueryable<TEntity>,
                IOrderedQueryable<TEntity>> orderBy = null,
            List<Expression<Func<TEntity, object>>>
                includeProperties = null,
            int? page = null,
            int? pageSize = null)
        {
            IQueryable<TEntity> query = DbSet;
            
            if (includeProperties != null)
                includeProperties.ForEach(i => { query = query.Include(i); });

            if (filter != null)
                query = query.Where(filter);

            if (orderBy != null)
                query = orderBy(query);

            if (page != null && pageSize != null)
                query = query
                    .Skip((page.Value - 1)*pageSize.Value)
                    .Take(pageSize.Value);

            return query;
        }
    }

Our generic implementation for Repository allows us to have have all our basic heavy lifting of a Repository out of the box for any one of our Entities. All we have to do is request for the Repository of interest by passing in the Entity e.g.

UnitOfWork.Repository<Customer>

will give us the Customer Repository with all our out of the box plumbing available.

Let’s take a quick look at our Get method in the Repository implementation.


        internal IEnumerable<TEntity> Get(
            Expression<Func<TEntity, bool>> filter = null,
            Func<IQueryable<TEntity>,
                IOrderedQueryable<TEntity>> orderBy = null,
            List<Expression<Func<TEntity, object>>>
                includeProperties = null,
            int? page = null,
            int? pageSize = null)
        {
            IQueryable<TEntity> query = DbSet;
            
            if (includeProperties != null)
                includeProperties.ForEach(i => query.Include(i));

            if (filter != null)
                query = query.Where(filter);

            if (orderBy != null)
                query = orderBy(query);

            if (page != null && pageSize != null)
                query = query
                    .Skip((page.Value - 1)*pageSize.Value)
                    .Take(pageSize.Value);


            return query.ToList();
        }

The Get method here, handles fetching data. It handles querying the data supporting a filtering, ordering, paging, and eager loading of child types, so that we can make one round trip and eager load the entity graph.

We notice here that the method is marked “internal”, this is because we only want the Get method here to be accessible to objects with the same assembly, Repository.dll. We will expose the Get method via the Query method and return the RepositoryQuery object to provide a fluent “ish” api, so that’s its a bit more easy and intuitive for our developers when querying with our Repository layer. Note, only methods in our RepositoryQuery will actually invoke the internal Get method, again, which is why we went ahead and marked the Get method internal.

Repository.RepositoryQuery.cs (our fluent api helper class)


    public sealed class RepositoryQuery<TEntity> where TEntity : class
    {
        private readonly List<Expression<Func<TEntity, object>>> 
            _includeProperties;

        private readonly Repository<TEntity> _repository;
        private Expression<Func<TEntity, bool>> _filter;
        private Func<IQueryable<TEntity>, 
            IOrderedQueryable<TEntity>> _orderByQuerable;
        private int? _page;
        private int? _pageSize;

        public RepositoryQuery(Repository<TEntity> repository)
        {
            _repository = repository;
            _includeProperties = 
                new List<Expression<Func<TEntity, object>>>();
        }

        public RepositoryQuery<TEntity> Filter(
            Expression<Func<TEntity, bool>> filter)
        {
            _filter = filter;
            return this;
        }

        public RepositoryQuery<TEntity> OrderBy(
            Func<IQueryable<TEntity>, IOrderedQueryable<TEntity>> orderBy)
        {
            _orderByQuerable = orderBy;
            return this;
        }

        public RepositoryQuery<TEntity> Include(
            Expression<Func<TEntity, object>> expression)
        {
            _includeProperties.Add(expression);
            return this;
        }

        public IEnumerable<TEntity> GetPage(
            int page, int pageSize, out int totalCount)
        {
            _page = page;
            _pageSize = pageSize;
            totalCount = _repository.Get(_filter).Count();

            return _repository.Get(
                _filter, 
                _orderByQuerable, _includeProperties, _page, _pageSize);
        }

        public IEnumerable<TEntity> Get()
        {
            return _repository.Get(
                _filter, 
                _orderByQuerable, _includeProperties, _page, _pageSize);
        }
    }

Addressing IRepository<TEntity> Extensibility

Well, what happens if we need extra methods a specific Repository? Meaning, how do we address “extensiblility” in our Repository? No problem, we have a couple of options here, we can simply inherit a Repository and add your own methods to it, or what I prefer, create extension methods e.g. extending IRepository (with some pseudo code for validating an address with UPS).

Repository.CustomerRepository.cs

    /// <summary>
    /// Extending the IRepository<Customer>
    /// </summary>
    public static class CustomerRepository
    {
        public static decimal GetCustomerOrderTotalByYear(
            this IRepository<Customer> customerRepository, 
            int customerId, int year)
        {
            return customerRepository
                .FindById(customerId)
                .Orders.SelectMany(o => o.OrderDetails)
                .Select(o => o.Quantity*o.UnitPrice).Sum();
        }

    /// <summary>
    /// TODO:
    /// This should really live in the Services project (Business Layer), 
    /// however, we'll leave it here for now as an example, and migrate
    /// this in the next post.
    /// </summary>
        public static void AddCustomerWithAddressValidation(
            this IRepository<Customer> customerRepository, Customer customer)
        {
            USPSManager m = new USPSManager("YOUR_USER_ID", true);
            Address a = new Address();
            a.Address1 = customer.Address;
            a.City = customer.City;

            Address validatedAddress = m.ValidateAddress(a);

            if (validatedAddress != null)
            customerRepository.InsertGraph(customer);
        }
    }

Great, now that we have our project nicely structured with the our generic implementation of the Unit of Work and Repository Pattern, let’s see how we can leverage this by wiring up a simple controller to show a list of customers.

To help us with this go ahead and NuGet the PagedList for MVC so we easily create a view with a paged grid.

5-10-2013 6-22-37 PM

Let’s create a CustomerController Index Action load a paged list of customers to hydrate a grid.


    public class CustomerController : Controller
    {
        public ActionResult Index(int? page)
        {
            var pageNumber = page ?? 1;
            const int pageSize = 20;

            var unitOfWork = new UnitOfWork();

            int totalCustomerCount;

            var customers =
                unitOfWork.Repository<Customer>()
                    .Query()
                    .Include(i => i.CustomerDemographics)
                    .OrderBy(q => q
                        .OrderBy(c => c.ContactName)
                        .ThenBy(c => c.CompanyName))
                    .Filter(q => q.ContactName != null)
                    .GetPage(pageNumber, pageSize, out totalCustomerCount);

            ViewBag.Customers = new StaticPagedList<Customer>(
                customers, pageNumber, pageSize, totalCustomerCount);

            unitOfWork.Save();

            return View();
        }
    }

Next, let’s wire up the Index.cshtml view for our CustomerController Index Action.


@{
    ViewBag.Title = "Customers";
}

@using PagedList.Mvc;
@using PagedList;

<h2>Customers</h2>

<link href="/Content/PagedList.css" rel="stylesheet" type="text/css" />

<h2>List of Customers</h2>

<p>
    @Html.ActionLink("Create New", "Create")
</p>
<table style="width: 100%; padding: 10px;">
    <tr style="background-color: lightgray; padding: 10px;">
        <th>#</th>
        <th>Company
        </th>
        <th>Name
        </th>
        <th>Title
        </th>
        <th>Order Date
        </th>
    </tr>

    @foreach (var item in ViewBag.Customers)
    {
        <tr>
            <td>
                @Html.ActionLink(
                    "Edit", "Edit", new { id = item.CustomerID }) |

                @Html.ActionLink(
                    "Details", "Details", new { id = item.CustomerID }) |

                @Html.ActionLink(
                    "Delete", "Delete", new { id = item.CustomerID })
            </td>
            <td>
                @item.CompanyName
            </td>
            <td>
                @item.ContactName
            </td>
            <td>
                @item.ContactTitle
            </td>
            <td>
                @if (item.Orders.Count > 1)
                {
                    @item.Orders[1].OrderDate.ToShortDateString()
                }
            </td>
        </tr>
    }


    <tr>
        <td colspan="9">
            @Html.PagedListPager(
                (IPagedList)ViewBag.Customers, page => 
                    Url.Action("Index", new { page }))
        </td>
    </tr>

</table>


Go ahead and run our project to see our paged customers grid.

5-10-2013 6-46-30 PM

Abstracting the Complexity when Dealing with Entity Graphs

Another item I wanted to go over was insert and updating graphs with our Repository pattern. There are four use cases for inserting graphs, they are as follows.

5-10-2013 7-34-28 PM

To abstract the complexity and EF experience required, and how the DbContext manages graphs e.g to know to set the root entity state and how it affects other entities in the graph (e.g. updating the root entity in the graph, and existing entities in the graph are to be updated or deleted) we added a interface IOjectState that all of our entities will implement.

Entities.IObjectState.cs


namespace Data
{
    public interface IObjectState
    {
        ObjectState State { get; set; }
    }
}

Entities.ObjectState.cs (enum)


namespace Data
{
    public enum ObjectState
    {
        Unchanged,
        Added,
        Modified,
        Deleted
    }
}

These two classes will allow our development team to explicitly set the state of each of the entities in the graph when inserting or updating a graph. To make use of the classes we’ll need to extend the DbContext with a few methods, we’ll do this by creating extension methods.

Data.DbContextExtension.cs


    public static class DbContextExtension
    {
        public static void ApplyStateChanges(this DbContext dbContext)
        {
            foreach (var dbEntityEntry in dbContext.ChangeTracker.Entries())
            {
                var entityState = dbEntityEntry.Entity as IObjectState;
                if (entityState == null)
                    throw new InvalidCastException(
                        "All entites must implement " +
                        "the IObjectState interface, this interface " +
                        "must be implemented so each entites state" +
                        "can explicitely determined when updating graphs.");

                dbEntityEntry.State = ConvertState(entityState.State);
            }
        }

        private static EntityState ConvertState(ObjectState state)
        {
            switch (state)
            {
                case ObjectState.Added:
                    return EntityState.Added;
                case ObjectState.Modified:
                    return EntityState.Modified;
                case ObjectState.Deleted:
                    return EntityState.Deleted;
                default:
                    return EntityState.Unchanged;
            }
        }
    }

Now we will override the SaveChanges in our NorthwindContext to invoke the ApplyStateChanges method to synchronize our ObjectSate with EF’s EntityState, so that the context will know how to deal with each and every entity when dealing with entity graphs.

Data.NorthwindContext.SaveChanges()


        public override int SaveChanges()
        {
            this.ApplyStateChanges();
            return base.SaveChanges();
        }


Now when inserting, updating you can explicitly set the entities state, especially useful when dealing with graphs. This abstracts the skill-set of a developer using our Repository of having to know the what, when and how to set the state of entities in the graph in order for the context to update the graph and persist the graph correctly. Let’s take a look at an example of updating an existing Order and adding an OrderDetail item with an entity graph. Both these actions, are will be executed on the same graph, however notice that the action is different for both of the entity’s, one is updating and the other is adding, however we will only be invoking one method (IRepository.Update(TEntity entity) from our IRepository in one transaction.

So we’ll demonstrate and prove out updating an entity graph with our UnitOfWork implementation in these steps.

Code Snippet from LinqPad, notice how we are explicitly setting each of the entities state in the entity graph.


var unitOfWork = new UnitOfWork(this);

var orderId = 10253;

unitOfWork
	.Repository<Order>()
	.Query()
	.Include(t => t.Customer)
	.Filter(t=> t.OrderID == orderId)
	.Get().Dump();

var order = unitOfWork
	.Repository<Order>()
	.FindById(orderId);

unitOfWork
	.Repository<OrderDetail>()
	.Query()
	.Filter(t => t.OrderID == orderId)
	.Get().Dump();

order.ShipName = "Long Le";
order.State = ObjectState.Modified;

order.OrderDetails.Add(
	new OrderDetail{
		ProductID = 2,
		UnitPrice = 10,
		Quantity = 2,
		Discount = 1,
		State = ObjectState.Added
	}
);


unitOfWork.Repository<Order>()
	.Update(order);

unitOfWork.Save();

new UnitOfWork(this)
	.Repository<Order>()
	.Query()
	.Include(t => t.Customer)
	.Filter(t => t.OrderID == orderId)
	.Get().Dump();
	
new UnitOfWork(this)
	.Repository<OrderDetail>()
	.Query()
	.Filter(t => t.OrderID == orderId)
	.Get().Dump();
		

Entity Graph Update Scenario

  1. Query the Order table, make note of the ShipName value.
  2. Query the OrderDetail table, make not there are only three (3) items, that belong to the same Order.
  3. Update the ShipName value in the Order.
  4. Add an OrderDetail to the Order.

5-11-2013 4-13-23 PM

(click image to enlarge)

Presto, we were able to successfully update an existing Order and add a new OrderDetail via an entity graph with one transaction using one method. Now, we can absolutely do this using EF out of the box, however, our goal here is was to abstract the complexity and skill set required from a developer in regards to EF specially how do deal with the DbContext in order to make this happen as well as obviously still support working with graphs through our IRepository implementation.

There you have it, and extensible genericized implementation of the UoW and Repository pattern with EF in MVC. In the next blog post, we’ll add DI & IoC to this solution and introduce the Services layer, this layer will house all of our business logic and rules. We will also implement the Services layer in a way, where we don’t violate our Unit of Work pattern, meaning all the work done in our Repository and Services are executed under one single instance the DbContext per page request.

Happy Coding..! :)

Download sample: https://genericunitofworkandrepositories.codeplex.com