Because the DbContext has been disposed. #238 | Support Center

sayram created 9 years ago

I have a CategoryService I'm using a method like below

public IEnumerable<Category> GetCategories(ContentState state)
        {
            var categories = _categoryRepository.GetAll().Where(c => c.CategoryState == state.ToString());

            //var categories = _categoryRepository.GetAllList(c => c.CategoryState == state.ToString());
            return categories;
        }

this is the AddCategory method in controller

public ActionResult AddCategory()
        {
            var categories = _categoryService.GetCategories(ContentState.Published);
            var viewModel = new CreateCategoryViewModel
            {
                Categories = categories.ToSelectListItems(-1),
            };

            return View(viewModel);
        }

Btw this is the ContentState

public enum ContentState
    {
        Published,
        Unpublished,
        Trashed,
        Pending
    }

and thi is the Category entity

public partial class Category : Entity
    {
        public Category()
        {
            this.SubCategories = new List<Category>();
            this.Videos = new List<Video>();
        }

        public int? ParentId { get; set; }
        public string Title { get; set; }
        public string Description { get; set; }
        public string MetaKeys { get; set; }
        public string MetaDescription { get; set; }
        public string CategoryState { get; set; }
        public virtual ICollection<Category> SubCategories { get; set; }
        public virtual Category ParentCategory { get; set; }
    }

Viewmodel

public class CreateCategoryViewModel 
    {
        public int Id { get; set; }
        public int? ParentId { get; set; }
        public string Title { get; set; }
        public string Description { get; set; }
        public string MetaKeys { get; set; }
        public string MetaDescription { get; set; }
        public string CategoryState { get; set; }
        public string Button { get; set; }
        //public string ActionMessage { get; set; }

        public IEnumerable<SelectListItem> Categories { get; set; }

    }

this is the where i get the error

@helper PrintCategories(dynamic categories)
{
    foreach (var item in categories)
    {
        @item.Title
        <br />
        var subCategories = item.SubCategories;
        if (subCategories != null && subCategories.Count > 0)
        {
            PrintCategories(subCategories);
        }
    }
}
                            <div class="form-group">
                                <div class="col-lg-10">
                                    @PrintCategories(Model.Categories)
                                </div>
                            </div>

so when im trying to access navigation property i get this error

The operation cannot be completed because the DbContext has been disposed. Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.InvalidOperationException: The operation cannot be completed because the DbContext has been disposed.

Stack Trace

[InvalidOperationException: The operation cannot be completed because the DbContext has been disposed.]
   System.Data.Entity.Internal.LazyInternalContext.InitializeContext() +762
   System.Data.Entity.Internal.Linq.InternalQuery`1.GetEnumerator() +28
   System.Data.Entity.Infrastructure.DbQuery`1.System.Collections.IEnumerable.GetEnumerator() +52
   ASP.<>c__DisplayClassd.<PrintCategories>b__c(TextWriter __razor_helper_writer) in c:\Users\saYRam\Documents\Visual Studio 2013\Projects\Index Projects\Index.Web\Areas\Administrator\Views\Category\AddCategory.cshtml:82
   System.Web.WebPages.HelperResult.WriteTo(TextWriter writer) +10
   System.Web.WebPages.WebPageBase.Write(HelperResult result) +80
   ASP._Page_Areas_Administrator_Views_Category_AddCategory_cshtml.Execute() in c:\Users\saYRam\Documents\Visual Studio 2013\Projects\Index Projects\Index.Web\Areas\Administrator\Views\Category\AddCategory.cshtml:71
   System.Web.WebPages.WebPageBase.ExecutePageHierarchy() +197
   System.Web.Mvc.WebViewPage.ExecutePageHierarchy() +105
   System.Web.WebPages.StartPage.RunPage() +17
   System.Web.WebPages.StartPage.ExecutePageHierarchy() +64
   System.Web.WebPages.WebPageBase.ExecutePageHierarchy(WebPageContext pageContext, TextWriter writer, WebPageRenderingBase startPage) +78
   System.Web.Mvc.RazorView.RenderView(ViewContext viewContext, TextWriter writer, Object instance) +235
   System.Web.Mvc.BuildManagerCompiledView.Render(ViewContext viewContext, TextWriter writer) +107
   System.Web.Mvc.ViewResultBase.ExecuteResult(ControllerContext context) +291
   System.Web.Mvc.ControllerActionInvoker.InvokeActionResult(ControllerContext controllerContext, ActionResult actionResult) +13
   System.Web.Mvc.ControllerActionInvoker.InvokeActionResultFilterRecursive(IList`1 filters, Int32 filterIndex, ResultExecutingContext preContext, ControllerContext controllerContext, ActionResult actionResult) +56
   System.Web.Mvc.ControllerActionInvoker.InvokeActionResultFilterRecursive(IList`1 filters, Int32 filterIndex, ResultExecutingContext preContext, ControllerContext controllerContext, ActionResult actionResult) +420
   System.Web.Mvc.ControllerActionInvoker.InvokeActionResultWithFilters(ControllerContext controllerContext, IList`1 filters, ActionResult actionResult) +52
   System.Web.Mvc.Async.&lt;&gt;c__DisplayClass2b.&lt;BeginInvokeAction&gt;b__1c() +173
   System.Web.Mvc.Async.&lt;&gt;c__DisplayClass21.&lt;BeginInvokeAction&gt;b__1e(IAsyncResult asyncResult) +100
   System.Web.Mvc.Async.WrappedAsyncResult`1.CallEndDelegate(IAsyncResult asyncResult) +10
   System.Web.Mvc.Async.WrappedAsyncResultBase`1.End() +49
   System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeAction(IAsyncResult asyncResult) +27
   System.Web.Mvc.Controller.&lt;BeginExecuteCore&gt;b__1d(IAsyncResult asyncResult, ExecuteCoreState innerState) +13
   System.Web.Mvc.Async.WrappedAsyncVoid`1.CallEndDelegate(IAsyncResult asyncResult) +29
   System.Web.Mvc.Async.WrappedAsyncResultBase`1.End() +49
   System.Web.Mvc.Controller.EndExecuteCore(IAsyncResult asyncResult) +36
   System.Web.Mvc.Controller.&lt;BeginExecute&gt;b__15(IAsyncResult asyncResult, Controller controller) +12
   System.Web.Mvc.Async.WrappedAsyncVoid`1.CallEndDelegate(IAsyncResult asyncResult) +22
   System.Web.Mvc.Async.WrappedAsyncResultBase`1.End() +49
   System.Web.Mvc.Controller.EndExecute(IAsyncResult asyncResult) +26
   System.Web.Mvc.Controller.System.Web.Mvc.Async.IAsyncController.EndExecute(IAsyncResult asyncResult) +10
   System.Web.Mvc.MvcHandler.&lt;BeginProcessRequest&gt;b__5(IAsyncResult asyncResult, ProcessRequestState innerState) +21
   System.Web.Mvc.Async.WrappedAsyncVoid`1.CallEndDelegate(IAsyncResult asyncResult) +29
   System.Web.Mvc.Async.WrappedAsyncResultBase`1.End() +49
   System.Web.Mvc.MvcHandler.EndProcessRequest(IAsyncResult asyncResult) +28
   System.Web.Mvc.MvcHandler.System.Web.IHttpAsyncHandler.EndProcessRequest(IAsyncResult result) +9
   System.Web.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +9723757
   System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +155

I think its related Lazy Loading which is i realy scared when i hear its name. I have no idea how can i get rid of this.

7 Answer(s)

0

hikalkan created 9 years ago
Support Team

You can not return IQueryable from application service method. Just use ToList() after Where condition.

sayram created 9 years ago

<cite>hikalkan: </cite> You can not return IQueryable from application service method. Just use ToList() after Where condition.

changed code below

...
            var categories = _categoryRepository.GetAll().Where(c => c.CategoryState == state.ToString());
...

...
            var categories = _categoryRepository.GetAll().Where(c => c.CategoryState == state.ToString()).ToList();
...

This time a get this error.

The ObjectContext instance has been disposed and can no longer be used for operations that require a connection.

Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.ObjectDisposedException: The ObjectContext instance has been disposed and can no longer be used for operations that require a connection.

This is the Stack trace

[ObjectDisposedException: The ObjectContext instance has been disposed and can no longer be used for operations that require a connection.]
   System.Data.Entity.Core.Objects.ObjectContext.get_Connection() +91
   System.Data.Entity.Core.Objects.ObjectQuery`1.GetResults(Nullable`1 forMergeOption) +273
   System.Data.Entity.Core.Objects.ObjectQuery`1.Execute(MergeOption mergeOption) +83
   System.Data.Entity.Core.Objects.DataClasses.EntityCollection`1.Load(List`1 collection, MergeOption mergeOption) +203
   System.Data.Entity.Core.Objects.DataClasses.EntityCollection`1.Load(MergeOption mergeOption) +51
   System.Data.Entity.Core.Objects.DataClasses.RelatedEnd.Load() +59
   System.Data.Entity.Core.Objects.DataClasses.RelatedEnd.DeferredLoad() +438
   System.Data.Entity.Core.Objects.Internal.LazyLoadBehavior.LoadProperty(TItem propertyValue, String relationshipName, String targetRoleName, Boolean mustBeNull, Object wrapperObject) +165
   System.Data.Entity.Core.Objects.Internal.<>c__DisplayClass7`2.&lt;GetInterceptorDelegate&gt;b__1(TProxy proxy, TItem item) +205
   System.Data.Entity.DynamicProxies.Category_93B8F10007F4823D6C15308F82C291EDF6CC0E4BAC3D32B099E0561F771A5140.get_SubCategories() +75
   CallSite.Target(Closure , CallSite , Object ) +189
   System.Dynamic.UpdateDelegates.UpdateAndExecute1(CallSite site, T0 arg0) +517
   ASP.&lt;&gt;c__DisplayClassd.&lt;PrintCategories&gt;b__c(TextWriter __razor_helper_writer) in c:\Users\saYRam\Documents\Visual Studio 2013\Projects\Index Projects\Index.Web\Areas\Administrator\Views\Category\AddCategory.cshtml:82
   System.Web.WebPages.HelperResult.WriteTo(TextWriter writer) +42
   System.Web.WebPages.WebPageExecutingBase.WriteTo(TextWriter writer, HelperResult content) +45
   System.Web.WebPages.WebPageBase.Write(HelperResult result) +53
   ASP._Page_Areas_Administrator_Views_Category_AddCategory_cshtml.Execute() in c:\Users\saYRam\Documents\Visual Studio 2013\Projects\Index Projects\Index.Web\Areas\Administrator\Views\Category\AddCategory.cshtml:91
   System.Web.WebPages.WebPageBase.ExecutePageHierarchy() +270
   System.Web.Mvc.WebViewPage.ExecutePageHierarchy() +122
   System.Web.WebPages.StartPage.RunPage() +63
   System.Web.WebPages.StartPage.ExecutePageHierarchy() +100
   System.Web.WebPages.WebPageBase.ExecutePageHierarchy(WebPageContext pageContext, TextWriter writer, WebPageRenderingBase startPage) +131
   System.Web.Mvc.RazorView.RenderView(ViewContext viewContext, TextWriter writer, Object instance) +695
   System.Web.Mvc.BuildManagerCompiledView.Render(ViewContext viewContext, TextWriter writer) +382
   System.Web.Mvc.ViewResultBase.ExecuteResult(ControllerContext context) +431
   System.Web.Mvc.ControllerActionInvoker.InvokeActionResult(ControllerContext controllerContext, ActionResult actionResult) +39
   System.Web.Mvc.ControllerActionInvoker.InvokeActionResultFilterRecursive(IList`1 filters, Int32 filterIndex, ResultExecutingContext preContext, ControllerContext controllerContext, ActionResult actionResult) +116
   System.Web.Mvc.ControllerActionInvoker.InvokeActionResultFilterRecursive(IList`1 filters, Int32 filterIndex, ResultExecutingContext preContext, ControllerContext controllerContext, ActionResult actionResult) +529
   System.Web.Mvc.ControllerActionInvoker.InvokeActionResultWithFilters(ControllerContext controllerContext, IList`1 filters, ActionResult actionResult) +106
   System.Web.Mvc.Async.<>c__DisplayClass2b.<BeginInvokeAction>b__1c() +321
   System.Web.Mvc.Async.<>c__DisplayClass21.<BeginInvokeAction>b__1e(IAsyncResult asyncResult) +185
   System.Web.Mvc.Async.WrappedAsyncResult`1.CallEndDelegate(IAsyncResult asyncResult) +42
   System.Web.Mvc.Async.WrappedAsyncResultBase`1.End() +133
   System.Web.Mvc.Async.AsyncResultWrapper.End(IAsyncResult asyncResult, Object tag) +56
   System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeAction(IAsyncResult asyncResult) +40
   System.Web.Mvc.Controller.<BeginExecuteCore>b__1d(IAsyncResult asyncResult, ExecuteCoreState innerState) +34
   System.Web.Mvc.Async.WrappedAsyncVoid`1.CallEndDelegate(IAsyncResult asyncResult) +70
   System.Web.Mvc.Async.WrappedAsyncResultBase`1.End() +133
   System.Web.Mvc.Async.AsyncResultWrapper.End(IAsyncResult asyncResult, Object tag) +56
   System.Web.Mvc.Async.AsyncResultWrapper.End(IAsyncResult asyncResult, Object tag) +37
   System.Web.Mvc.Controller.EndExecuteCore(IAsyncResult asyncResult) +44
   System.Web.Mvc.Controller.<BeginExecute>b__15(IAsyncResult asyncResult, Controller controller) +39
   System.Web.Mvc.Async.WrappedAsyncVoid`1.CallEndDelegate(IAsyncResult asyncResult) +62
   System.Web.Mvc.Async.WrappedAsyncResultBase`1.End() +133
   System.Web.Mvc.Async.AsyncResultWrapper.End(IAsyncResult asyncResult, Object tag) +56
   System.Web.Mvc.Async.AsyncResultWrapper.End(IAsyncResult asyncResult, Object tag) +37
   System.Web.Mvc.Controller.EndExecute(IAsyncResult asyncResult) +39
   System.Web.Mvc.Controller.System.Web.Mvc.Async.IAsyncController.EndExecute(IAsyncResult asyncResult) +39
   System.Web.Mvc.MvcHandler.<BeginProcessRequest>b__5(IAsyncResult asyncResult, ProcessRequestState innerState) +39
   System.Web.Mvc.Async.WrappedAsyncVoid`1.CallEndDelegate(IAsyncResult asyncResult) +70
   System.Web.Mvc.Async.WrappedAsyncResultBase`1.End() +133
   System.Web.Mvc.Async.AsyncResultWrapper.End(IAsyncResult asyncResult, Object tag) +56
   System.Web.Mvc.Async.AsyncResultWrapper.End(IAsyncResult asyncResult, Object tag) +37
   System.Web.Mvc.MvcHandler.EndProcessRequest(IAsyncResult asyncResult) +40
   System.Web.Mvc.MvcHandler.System.Web.IHttpAsyncHandler.EndProcessRequest(IAsyncResult result) +38
   System.Web.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +9723757
   System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +155

i really did not understood why and where i made mistake.

0

hikalkan created 9 years ago
Support Team

I believe that you willl understand it if you check <a class="postlink" href="http://www.aspnetboilerplate.com/Pages/Documents/Unit-Of-Work">http://www.aspnetboilerplate.com/Pages/ ... it-Of-Work</a> document.

If you're using your app service directly (without an interface), your method should be virtual. Also, service should implement IApplicationService.. etc. Please read document carefully since you may get same exception in different situations without understanding the reason completely. Especially here: <a class="postlink" href="http://www.aspnetboilerplate.com/Pages/Documents/Unit-Of-Work#DocRepositoryGetAll">http://www.aspnetboilerplate.com/Pages/ ... toryGetAll</a>

omar created 9 years ago

I am having the same issue when using AbpApiController.

public class UsersController : AbpApiController
    {
        private readonly IRepository<User, long> _userRepo;
      
        public UsersController(  IRepository<User,long> userRepo)
        {     
            _userRepo = userRepo;
        }

        [HttpGet]
        [UnitOfWork]
        public virtual dynamic GetAll()
        {
           return _userRepo.GetAllList();
        } 
    }

0

hikalkan created 9 years ago
Support Team

You should not return Entity to the client, instead use DTO. Why? See DTO document: <a class="postlink" href="http://www.aspnetboilerplate.com/Pages/Documents/Data-Transfer-Objects">http://www.aspnetboilerplate.com/Pages/ ... er-Objects</a> (especially, Serialization & lazy load problems section)
0
paddyfink created 9 years ago
Hey there, I'm having the same issue in a mvc controller.

public ActionResult Grid_Read([DataSourceRequest] DataSourceRequest request) { var suppliers = GetAll(); return Json(suppliers.ToDataSourceResult(request)); } [UnitOfWork] public virtual IEnumerable<SupplierListOutput> GetAll() { return _supplierRepository.GetAll().ProjectTo<SupplierListOutput>(); }

I'm using kendo ui Grid component that can performs filtering, sorting, paging.... That's why I need to have a direct acces to the repository in my controller and pass a IQueryable variable in my action method .

But I stilll have the error : The operation cannot be completed because the DbContext has been disposed.

The repository is injected in the controller constructor
0

hikalkan created 9 years ago
Support Team

Hi,

You can not return IQueryable from a Controller since database connection is closed after your method. Then KendoUI fetches quest while connection is closed.

If you really need to return IQueryable, then you should manage connection yourself. How? I did similar thing in odata sample. I started UOW manually (<a class="postlink" href="http://www.aspnetboilerplate.com/Pages/Documents/Zero/Edition-Management">http://www.aspnetboilerplate.com/Pages/ ... Management</a>) and finished manually (<a class="postlink" href="https://github.com/aspnetboilerplate/sample-odata/blob/master/src/AbpODataDemo.WebApi/Controllers/AbpODataEntityController.cs#L122">https://github.com/aspnetboilerplate/sa ... er.cs#L122</a>). You can implement similar thing for you.

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