Microsoft.VisualStudio.ProjectSystem.Query.QueryExecutionException during migration from Net48 to Ne-CodePudding

I am trying to migrate my project from net48 to net6. After targeting to net60 a have lof warnings:

Also, when I open project properties I see the following error:

Microsoft.VisualStudio.ProjectSystem.Query.QueryExecutionException: Object reference not set to an instance of an object. ---> System.NullReferenceException: Object reference not set to an instance of an object.
   at Microsoft.VisualStudio.LanguageServices.CSharp.ProjectSystemShim.EntryPointFinder.FindEntryPoints(INamespaceSymbol symbol)
   at Microsoft.VisualStudio.ProjectSystem.Properties.StartupObjectsEnumGenerator.<GetListedValuesAsync>d__8.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at Microsoft.VisualStudio.ProjectSystem.PropertyPages.PageDynamicEnumProperty.<CreateAdmissibleValuesAsync>d__6.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.VisualStudio.ProjectSystem.VS.Query.SupportedValueDataProducer.<CreateSupportedValuesAsync>d__1.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.VisualStudio.ProjectSystem.VS.Query.QueryDataFromProviderStateProducerBase`1.<SendRequestAsync>d__0.MoveNext()
   --- End of inner exception stack trace ---
   at Microsoft.VisualStudio.ProjectSystem.Query.QueryExecution.QuerySubscription`1.<RunQueryOnceAsync>d__9.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.VisualStudio.ProjectSystem.Query.QueryExecution.QuerySubscription`1.<>c__DisplayClass8_0.<<Start>b__0>d.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.VisualStudio.ProjectSystem.VS.Implementation.PropertyPages.Designer.ProjectPropertyDataAccess.Observer.<InitializeAsync>d__10.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter`1.GetResult()
   at Microsoft.VisualStudio.ProjectSystem.VS.Implementation.PropertyPages.Designer.ProjectPropertyDataAccess.Observer.<CreateAsync>d__9.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.VisualStudio.ProjectSystem.VS.Implementation.PropertyPages.Designer.ProjectPropertiesEditor.<>c__DisplayClass0_0.<<-ctor>b__0>d.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.VisualStudio.ProjectSystem.VS.Implementation.PropertyPages.Designer.AsyncLoadContent.<>c__DisplayClass0_0.<<Initialize>b__0>d.MoveNext()

How to fix it?

CodePudding user response：

This error was partly related to this error, once I solved the main problem this error was fixed.

CodePudding user response：

Not sure how did u start your migration but this tool is helpful https://github.com/dotnet/upgrade-assistant