NullReferenceException occurs when to use the XAML designer

Question

After updating to the latest version of visual studio 2015, I am unable to use the XAML designer due to the fact that each time I attempt to open it a screen appears to inform me that a NullReferenceException has occurred.

I have tried the solution detailed in the post below, However, as I am not a HP user this solution didn't work for me.

Visual Studio 2015 (Community) designer shows NullReferenceException for blank Universal App

Please see the attached screenshot and error message below. Any help would be greatly appreciated

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

Server stack trace: 
   at Microsoft.VisualStudio.DesignTools.DesignerContract.Isolation.Primitives.IsolationBoundary.RemoteIsolationContext.<>c__DisplayClass14_0.<Microsoft.VisualStudio.DesignTools.DesignerContract.Isolation.Primitives.IsolationBoundary.IRemoteContext.CreateInstance>b__0()
   at Microsoft.VisualStudio.DesignTools.DesignerContract.Isolation.Remoting.ThreadMarshaler.<>c__DisplayClass47_0`1.<MarshalIn>b__0()
   at Microsoft.VisualStudio.DesignTools.DesignerContract.Isolation.Remoting.STAMarshaler.Call.InvokeWorker()
   at Microsoft.VisualStudio.DesignTools.DesignerContract.Isolation.Remoting.STAMarshaler.Call.Invoke(Boolean waitingInExternalCall)
   at Microsoft.VisualStudio.DesignTools.DesignerContract.Isolation.Remoting.STAMarshaler.InvokeCall(Call call)
   at Microsoft.VisualStudio.DesignTools.DesignerContract.Isolation.Remoting.STAMarshaler.DirectInvoke(Boolean inbound, Action action, Int32 sourceApartmentId, Int32 targetApartmentId, Int32 originId, WaitHandle aborted)
   at Microsoft.VisualStudio.DesignTools.DesignerContract.Isolation.Remoting.STAMarshaler.DirectInvokeInbound(Action action, Int32 targetApartmentId)
   at Microsoft.VisualStudio.DesignTools.DesignerContract.Isolation.Remoting.STAMarshaler.MarshalIn(Action action, Int32 targetApartmentId, CancellationToken cancelToken, CallSynchronizationMode syncMode, CallModality callModality, String methodName, String filePath, Int32 lineNumber)
   at Microsoft.VisualStudio.DesignTools.DesignerContract.Isolation.Remoting.ThreadMarshaler.MarshalIn(IRemoteObject targetObject, Action action, CallSynchronizationMode syncMode, CallModality callModality, ApartmentState apartmentState, String memberName, String filePath, Int32 lineNumber)
   at Microsoft.VisualStudio.DesignTools.DesignerContract.Isolation.Remoting.ThreadMarshaler.MarshalIn[TResult](IRemoteObject targetObject, Func`1 func, CallModality callModality, ApartmentState apartmentState, String memberName, String filePath, Int32 lineNumber)
   at Microsoft.VisualStudio.DesignTools.DesignerContract.Isolation.Primitives.IsolationBoundary.RemoteIsolationContext.Microsoft.VisualStudio.DesignTools.DesignerContract.Isolation.Primitives.IsolationBoundary.IRemoteContext.CreateInstance(String assemblyName, String assemblyCodeBase, String typeName)
   at System.Runtime.Remoting.Messaging.StackBuilderSink._PrivateProcessMessage(IntPtr md, Object[] args, Object server, Object[]& outArgs)
   at System.Runtime.Remoting.Messaging.StackBuilderSink.SyncProcessMessage(IMessage msg)

Exception rethrown at [0]: 
   at System.Runtime.Remoting.Proxies.RealProxy.HandleReturnMessage(IMessage reqMsg, IMessage retMsg)
   at System.Runtime.Remoting.Proxies.RealProxy.PrivateInvoke(MessageData& msgData, Int32 type)
   at Microsoft.VisualStudio.DesignTools.DesignerContract.Isolation.Primitives.IsolationBoundary.IRemoteContext.CreateInstance(String assemblyName, String assemblyCodeBase, String typeName)
   at Microsoft.VisualStudio.DesignTools.DesignerContract.Isolation.Primitives.IsolationBoundary.<>c__DisplayClass38_0`1.<CreateInstance>b__0(IRemoteContext c)
   at Microsoft.VisualStudio.DesignTools.DesignerContract.Isolation.Remoting.ThreadMarshaler.<>c__DisplayClass31_0`2.<MarshalOut>b__0()
   at Microsoft.VisualStudio.DesignTools.DesignerContract.Isolation.Remoting.STAMarshaler.Call.InvokeWorker()

System.NullReferenceException
Object reference not set to an instance of an object.
   at Microsoft.VisualStudio.DesignTools.DesignerContract.Isolation.Remoting.STAMarshaler.WaitForCompletion(NestedCallContext nestedCallContext, BlockingCall call, WaitHandle timeoutSignal)
   at Microsoft.VisualStudio.DesignTools.DesignerContract.Isolation.Remoting.STAMarshaler.MarshalOutSynchronous(Action action, Int32 targetApartmentId, WaitHandle aborted, WaitHandle timeoutSignal, CancellationToken cancelToken, String methodName, String filePath, Int32 lineNumber)
   at Microsoft.VisualStudio.DesignTools.DesignerContract.Isolation.Remoting.STAMarshaler.MarshalOut(Action action, Int32 targetApartmentId, WaitHandle aborted, CancellationToken cancelToken, CallSynchronizationMode syncMode, WaitHandle timeoutSignal, String methodName, String filePath, Int32 lineNumber)
   at Microsoft.VisualStudio.DesignTools.DesignerContract.Isolation.Remoting.ThreadMarshaler.MarshalOut[TValue](RemoteHandle`1 targetObject, Action action, CallSynchronizationMode syncMode, ApartmentState apartmentState, String methodName, String filePath, Int32 lineNumber)
   at Microsoft.VisualStudio.DesignTools.DesignerContract.Isolation.Remoting.ThreadMarshaler.MarshalOut[TResult,TValue](RemoteHandle`1 targetObject, Func`2 func, CallSynchronizationMode syncMode, ApartmentState apartmentState, String methodName, String filePath, Int32 lineNumber)
   at Microsoft.VisualStudio.DesignTools.DesignerContract.Isolation.Primitives.IsolationBoundary.CreateInstance[T](Type type)
   at Microsoft.VisualStudio.DesignTools.DesignerContract.Isolation.IsolatedObjectFactory.Initialize()
   at Microsoft.VisualStudio.DesignTools.DesignerHost.Services.VSIsolationService.CreateObjectFactory(IIsolationTarget isolationTarget, IObjectCatalog catalog)
   at Microsoft.VisualStudio.DesignTools.DesignerContract.Isolation.IsolationService.CreateLease(IIsolationTarget isolationTarget)
   at Microsoft.VisualStudio.DesignTools.DesignerContract.Isolation.IsolationService.CreateLease(IIsolationTarget isolationTarget)
   at Microsoft.VisualStudio.DesignTools.DesignerContract.IsolatedDesignerService.CreateLease(IIsolationTarget isolationTarget, CancellationToken cancelToken, DesignerServiceEntry& entry, IServiceProvider serviceOverrides)
   at Microsoft.VisualStudio.DesignTools.DesignerContract.IsolatedDesignerService.IsolatedDesignerView.CreateDesignerViewInfo(CancellationToken cancelToken)
   at Microsoft.VisualStudio.DesignTools.DesignerContract.Isolation.IsolatedTaskScheduler.InvokeWithCulture[T](CultureInfo culture, Func`2 func, CancellationToken cancelToken)
   at Microsoft.VisualStudio.DesignTools.DesignerContract.Isolation.IsolatedTaskScheduler.<>c__DisplayClass10_0`1.<StartTask>b__0()
   at System.Threading.Tasks.Task`1.InnerInvoke()
   at System.Threading.Tasks.Task.Execute()

ChrisF · Answer 1 · 2015-12-24T18:23:26.343

3

You will have some code in a constructor that relies on something that would normally be set only at runtime (a database connection for example).

You will need to wrap the code in a test like this:

if (!Windows.ApplicationModel.DesignMode.DesignModeEnabled)
{
    // Runtime mode specific functionality
}

Note The DesignModeEnabled property is available only in the presence of a developer certificate.

Source

You can either do this for all the code in the constructor or try to narrow it down so you only have the test round the minimum possible code. Alternatively you should look at moving that code out of the constructor into an OnLoaded event handler.

edited Dec 24 '15 at 18:23

answered Dec 24 '15 at 18:14

ChrisF

134,786
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1

This error occurs even with the default blank project. Thanks for the advice :-) – Tom Easterbrook Dec 24 '15 at 18:32
Hi, I have the same problem in VS 2019. How have you solved this issue? – Ionut Enache Oct 24 '19 at 07:35

score 0 · Answer 2 · answered Sep 20 '21 at 11:22

0

The same thing happened to me. I deleted the .vs, bin, obj directories in the project and it worked.

answered Sep 20 '21 at 11:22

Abbosbek Niyozqulov

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NullReferenceException occurs when to use the XAML designer

2 Answers2