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POMVC, EF - DataContext singleton instance Per-Web-Request in Unity
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  1. POMVC, EF - DataContext singleton instance Per-Web-Request in Unity
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    copied!<p>I have a MVC 3 web application, where I am using the Entity Framework for the data access. Furthermore, I have made a simple use of the repository pattern, where e.g. all Product related stuff is handled in the "ProductRepository" and all User related stuff is handled in the "UserRepository". </p> <p>Thus, I am using the UNITY container, to make a singleton instance of the DataContext, which I inject into each of the repositories. A quick search on Google, and everyone recommends you to NOT use a singleton instance of the DataContext, as it might give you some memory leaks in the future. </p> <p>So, inspired by this post, making a singleton instance of the DataContext for each web request is the answer (please correct me if I am wrong!)</p> <p><a href="http://blogs.microsoft.co.il/blogs/gilf/archive/2010/05/18/how-to-manage-objectcontext-per-request-in-asp-net.aspx" rel="nofollow noreferrer">http://blogs.microsoft.co.il/blogs/gilf/archive/2010/05/18/how-to-manage-objectcontext-per-request-in-asp-net.aspx</a></p> <p>However, UNITY does not support the "Per-web-request" lifetime manager. But, it is possible to implement your own custom lifetime manager, which handles this for you. Actually, this is discussed in this post : </p> <p><a href="https://stackoverflow.com/questions/1151201/singleton-per-call-context-web-request-in-unity">Singleton Per Call Context (Web Request) in Unity</a></p> <p>The question is, I have now implemented the custom lifetime manager as described in the above post, but I am unsure if this is the way to do it. I am also wondering about where the datacontext instance is disposed in the provided solution? Am I missing out something?</p> <p>Is there actually a better way of solving my "issue"?</p> <p>Thanks!</p> <h2>** Added information about my implementation **</h2> <p>The following is snippets from my Global.asax, Controller and Repository. This gives a clear picture of my implementation. </p> <p><strong>Global.asax</strong></p> <pre><code> var container = new UnityContainer(); container .RegisterType&lt;ProductsRepository&gt;(new ContainerControlledLifetimeManager()) .RegisterType&lt;CategoryRepository&gt;(new ContainerControlledLifetimeManager()) .RegisterType&lt;MyEntities&gt;(new PerResolveLifetimeManager(), dbConnectionString) </code></pre> <p><strong>Controller</strong> </p> <pre><code>private ProductsRepository _productsRepository; private CategoryRepository _categoryRepository; public ProductsController(ProductsRepository productsRepository, CategoryRepository categoryRepository) { _productsRepository = productsRepository; _categoryRepository = categoryRepository; } public ActionResult Index() { ProductCategory category = _categoryRepository.GetProductCategory(categoryId); . . . } protected override void Dispose(bool disposing) { base.Dispose(disposing); _productsRepository.Dispose(); _categoryRepository.Dispose(); } </code></pre> <p><strong>Product Repository</strong></p> <pre><code>public class ProductsRepository : IDisposable { private MyEntities _db; public ProductsRepository(MyEntities db) { _db = db; } public Product GetProduct(Guid productId) { return _db.Product.Where(x =&gt; x.ID == productId).FirstOrDefault(); } public void Dispose() { this._db.Dispose(); } </code></pre> <p><strong>Controller Factory</strong></p> <pre><code>public class UnityControllerFactory : DefaultControllerFactory { IUnityContainer _container; public UnityControllerFactory(IUnityContainer container) { _container = container; } protected override IController GetControllerInstance(RequestContext requestContext, Type controllerType) { if (controllerType == null) { throw new HttpException(404, String.Format("The controller for path '{0}' could not be found" + "or it does not implement IController.", requestContext.HttpContext.Request.Path)); } return _container.Resolve(controllerType) as IController; } } </code></pre> <p><strong>Addition information</strong> Hi, I will post additional links that I come across, concerning the related issue and solution suggestions: </p> <ol> <li><a href="http://cgeers.wordpress.com/2009/02/21/entity-framework-objectcontext/#objectcontext" rel="nofollow noreferrer">http://cgeers.wordpress.com/2009/02/21/entity-framework-objectcontext/#objectcontext</a></li> <li><a href="http://dotnetslackers.com/articles/ado_net/Managing-Entity-Framework-ObjectContext-lifespan-and-scope-in-n-layered-ASP-NET-applications.aspx" rel="nofollow noreferrer">http://dotnetslackers.com/articles/ado_net/Managing-Entity-Framework-ObjectContext-lifespan-and-scope-in-n-layered-ASP-NET-applications.aspx</a></li> <li><a href="https://stackoverflow.com/questions/2482220/attaching-linq-to-sql-datacontext-to-httpcontext-in-business-layer">attaching linq to sql datacontext to httpcontext in business layer</a></li> <li><a href="http://weblogs.asp.net/shijuvarghese/archive/2008/10/24/asp-net-mvc-tip-dependency-injection-with-unity-application-block.aspx" rel="nofollow noreferrer">http://weblogs.asp.net/shijuvarghese/archive/2008/10/24/asp-net-mvc-tip-dependency-injection-with-unity-application-block.aspx</a></li> <li><a href="http://msdn.microsoft.com/en-us/library/bb738470.aspx" rel="nofollow noreferrer">http://msdn.microsoft.com/en-us/library/bb738470.aspx</a></li> </ol>
 

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