Prism Template Pack - Error when Adding Xamarin.Forms ContentPage template item in .net standard shard project

Question

After migrating my Xamarin.Forms project to use shared .NET Standard project instead of PCL (folowing this link https://blog.xamarin.com/building-xamarin-forms-apps-net-standard/)

When I right click the shared project (.NET Standard proj) to Create a Xamarin.Forms ContentPage with Prism ViewModel using Prism Template Pack I get This Error :

The project system has encountered an error. Object reference not set to an instance of an object. A diagnostic log has been written to the following location: "C:\Users\toumir\AppData\Local\Temp\VsProjectFault_7c3ce3c8-085f-4531-99cf-85d9a8b8ceee.failure.txt".

Log file content:

04-09-2017 09:05:10
Recoverable
System.NullReferenceException: Object reference not set to an instance of an object.
   at Prism.VisualStudio.Wizards.CreateViewModelForViewWizard.RunFinished()
   at Microsoft.VisualStudio.TemplateWizard.Wizard.Execute(Object application, Int32 hwndOwner, Object[]& ContextParams, Object[]& CustomParams, wizardResult& retval)
   at System.Runtime.InteropServices.Marshal.ThrowExceptionForHRInternal(Int32 errorCode, IntPtr errorInfo)
   at Microsoft.VisualStudio.ErrorHandler.ThrowOnFailure(Int32 hr, Int32[] expectedHRFailure)
   at Microsoft.VisualStudio.ProjectSystem.VS.Implementation.Package.ProjectNode.RunWizard(SimpleHierarchyNode parentNode, String itemName, String wizardToRun, IntPtr dlgOwner)
   at Microsoft.VisualStudio.ProjectSystem.VS.Implementation.Package.ProjectNode.<AddItemWithSpecificAsync>d__602.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.VisualStudio.ProjectSystem.VS.Implementation.Package.ProjectNode.<>c__DisplayClass468_0.<<AddItem>b__0>d.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.VisualStudio.Threading.JoinableTask.CompleteOnCurrentThread()
   at Microsoft.VisualStudio.Threading.JoinableTask`1.CompleteOnCurrentThread()
   at Microsoft.VisualStudio.Threading.JoinableTaskFactory.Run[T](Func`1 asyncMethod, JoinableTaskCreationOptions creationOptions)
   at Microsoft.VisualStudio.ProjectSystem.ProjectMultiThreadedService.ExecuteSynchronously[T](Func`1 asyncAction)
   at Microsoft.VisualStudio.ProjectSystem.VS.Implementation.Package.ProjectNode.<>c__DisplayClass559_0.<HrInvoke>b__0()
   at Microsoft.VisualStudio.ProjectSystem.VS.HResult.Invoke(Func`1 action, IServiceProvider vsShellServiceProvider, IProjectFaultHandlerService projectFaultHandlerService, UnconfiguredProject project)
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at Microsoft.VisualStudio.ProjectSystem.CommonProjectSystemTools.Rethrow(Exception ex)
   at Microsoft.VisualStudio.ProjectSystem.ProjectErrorReporting.<>c__DisplayClass6_0.<SubmitErrorReport>b__0()
   at Microsoft.VisualStudio.ProjectSystem.ExceptionFilter.<>c__DisplayClass2_0.<Guard>b__0()
   at GuardMethodClass.GuardMethod(Func`1 , Func`2 , Func`2 )

and yet another message box showing this message:

Object reference not set to an instance of an object.

FYI:

• There is no problem when using PCL project
• My App class is derived from PrismApplication

Can anyone guide us? thanks in advance

Answer 1

The Prism Template Pack does not officially support the .NET Standard project format at this time. Xamarin does not ship with any .NET Standard compatible project templates, and Xamarin itself is not .NET Standard. When Xamarin is updated to .NET Standard, the Prism Template Pack will follow.