Server Error in '/' Application.

Object reference not set to an instance of an object.

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.NullReferenceException: Object reference not set to an instance of an object.

Source Error:


Line 37:   <h3>@einheit.Bezeichnung(culture)</h3>
Line 38:   <ul>
Line 39:     @foreach (var workshop in einheit.Workshops.Where(a=>a.TitelGER!= "Workshop noch nicht ausgewählt!").OrderBy(a=>a.Zeit).ThenBy(a=>a.Referenten.FirstOrDefault()?.Referent.Name))
Line 40:     {
Line 41:       <li><span style="@(culture=="en" && workshop.Sprache=="E" ? "font-weight:bold;" : "")">@workshop.Zeit @workshop.Titel(culture) @(workshop.Teil != null ? (culture == "en" ? "(Part " : "(Teil ") + workshop.Teil + ")" : "")</span> | 

Source File: C:\inetpub\webs\tcmkongress.at\Views\Kongress\DetailsTag.cshtml    Line: 39

Stack Trace:


[NullReferenceException: Object reference not set to an instance of an object.]
   ASP.<>c.<Execute>b__3_3(Workshop a) in C:\inetpub\webs\tcmkongress.at\Views\Kongress\DetailsTag.cshtml:39
   System.Linq.EnumerableSorter`2.ComputeKeys(TElement[] elements, Int32 count) +142
   System.Linq.EnumerableSorter`2.ComputeKeys(TElement[] elements, Int32 count) +253
   System.Linq.EnumerableSorter`1.Sort(TElement[] elements, Int32 count) +28
   System.Linq.<GetEnumerator>d__1.MoveNext() +272
   ASP._Page_Views_Kongress_DetailsTag_cshtml.Execute() in C:\inetpub\webs\tcmkongress.at\Views\Kongress\DetailsTag.cshtml:39
   System.Web.WebPages.WebPageBase.ExecutePageHierarchy() +251
   System.Web.Mvc.WebViewPage.ExecutePageHierarchy() +147
   System.Web.WebPages.StartPage.ExecutePageHierarchy() +85
   System.Web.WebPages.WebPageBase.ExecutePageHierarchy(WebPageContext pageContext, TextWriter writer, WebPageRenderingBase startPage) +106
   System.Web.Mvc.ViewResultBase.ExecuteResult(ControllerContext context) +377
   System.Web.Mvc.ControllerActionInvoker.InvokeActionResultFilterRecursive(IList`1 filters, Int32 filterIndex, ResultExecutingContext preContext, ControllerContext controllerContext, ActionResult actionResult) +90
   System.Web.Mvc.ControllerActionInvoker.InvokeActionResultFilterRecursive(IList`1 filters, Int32 filterIndex, ResultExecutingContext preContext, ControllerContext controllerContext, ActionResult actionResult) +795
   System.Web.Mvc.ControllerActionInvoker.InvokeActionResultWithFilters(ControllerContext controllerContext, IList`1 filters, ActionResult actionResult) +81
   System.Web.Mvc.Async.<>c__DisplayClass21.<BeginInvokeAction>b__1e(IAsyncResult asyncResult) +188
   System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeAction(IAsyncResult asyncResult) +38
   System.Web.Mvc.Controller.<BeginExecuteCore>b__1d(IAsyncResult asyncResult, ExecuteCoreState innerState) +32
   System.Web.Mvc.Async.WrappedAsyncVoid`1.CallEndDelegate(IAsyncResult asyncResult) +73
   System.Web.Mvc.Controller.EndExecuteCore(IAsyncResult asyncResult) +52
   System.Web.Mvc.Async.WrappedAsyncVoid`1.CallEndDelegate(IAsyncResult asyncResult) +39
   System.Web.Mvc.Controller.EndExecute(IAsyncResult asyncResult) +38
   System.Web.Mvc.MvcHandler.<BeginProcessRequest>b__5(IAsyncResult asyncResult, ProcessRequestState innerState) +46
   System.Web.Mvc.Async.WrappedAsyncVoid`1.CallEndDelegate(IAsyncResult asyncResult) +73
   System.Web.Mvc.MvcHandler.EndProcessRequest(IAsyncResult asyncResult) +38
   System.Web.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +426
   System.Web.HttpApplication.ExecuteStepImpl(IExecutionStep step) +172
   System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +158


Version Information: Microsoft .NET Framework Version:4.0.30319; ASP.NET Version:4.8.9220.0