The (none) text does not display for Choose Data Source item in the DataGridView Tasks dialog in DemoConsole application

[Zheng-Li01]

.NET version

main branch of Winforms repo

Did it work in .NET Framework?

Yes

Did it work in any of the earlier releases of .NET Core or .NET 5+?

No

Issue description

The (none) text does not display for Choose Data Source item in the DataGridView Tasks dialog in DemoConsole application
.NET 10:

.NET framework 4.8.1:

.NET Application:

Steps to reproduce

Test the sample app: DemoConsole in Winforms repo

[Tanya-Solyanik]

@ricardobossan , please root-cause this issue and report back.

[ricardobossan]

@Tanya-Solyanik My findings so far:

• The DataGridView Tasks dialog is displayed through the DesignerActionPanel.
• The DataSource value shown there comes from the designer class, specifically DataGridViewDesigner.
• The value of DataSource starts as null. If the user changes it to None in the dropdown, it is set back to null.
• When the value is null, the field appears empty in the Tasks dialog.
• A practical workaround is to return the string "(none)" when the DataSource property of DataGridViewDesigner is null, like so:

  public object? DataSource
  {
      get => _owner.DataSource ?? "(none)";
  }

[Tanya-Solyanik]

We shouldn't replace a null return value with a string, this is a public API, the customers are expecting and handling a null. How is this supposed to work? how does it work in the Inproc designer or OOP designer? Does this work when demo console is retargeted to NETFX?

[ricardobossan]

How is this supposed to work? how does it work in the Inproc designer or OOP designer?

• On OOP, I debugged a standard .NET 10 WinForms project (VPN on), and the "(none)" message appeared as expected in the field:
  
• I found one place where the string "(none)" appears during runtime. This seems to be the value returned from serialization:
  
• Here’s the call stack for that serialization:

  > Microsoft.DotNet.DesignTools.Protocol.dll!Microsoft.DotNet.DesignTools.Protocol.DataPipe.Binary.BinaryMessageFormatter.StreamJsonRpc.IJsonRpcMessageFormatter.Serialize(System.Buffers.IBufferWriter<byte> bufferWriter, StreamJsonRpc.Protocol.JsonRpcMessage message) Line 158 C#
  >
  > StreamJsonRpc.dll!StreamJsonRpc.LengthHeaderMessageHandler.Write(StreamJsonRpc.Protocol.JsonRpcMessage content, System.Threading.CancellationToken cancellationToken) Unknown
  > StreamJsonRpc.dll!StreamJsonRpc.MessageHandlerBase.WriteAsync(StreamJsonRpc.Protocol.JsonRpcMessage content, System.Threading.CancellationToken cancellationToken) Unknown
  > [Resuming Async Method]
  > System.Private.CoreLib.dll!System.Runtime.CompilerServices.AsyncMethodBuilderCore.Start<StreamJsonRpc.MessageHandlerBase.<WriteAsync>d**23>(ref StreamJsonRpc.MessageHandlerBase.<WriteAsync>d**23 stateMachine) Unknown
  > StreamJsonRpc.dll!StreamJsonRpc.JsonRpc.SendAsync(StreamJsonRpc.Protocol.JsonRpcMessage message, System.Threading.CancellationToken cancellationToken) Unknown
  > [Resuming Async Method]
  > System.Private.CoreLib.dll!System.Runtime.CompilerServices.AsyncMethodBuilderCore.Start<StreamJsonRpc.JsonRpc.<SendAsync>d**149>(ref StreamJsonRpc.JsonRpc.<SendAsync>d**149 stateMachine) Unknown
  > StreamJsonRpc.dll!StreamJsonRpc.JsonRpc.HandleRpcAsync(StreamJsonRpc.Protocol.JsonRpcMessage rpc) Unknown
  > [Resuming Async Method]
  > System.Private.CoreLib.dll!System.Threading.ExecutionContext.RunInternal(System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, object state) Unknown
  > System.Private.CoreLib.dll!System.Runtime.CompilerServices.AsyncTaskMethodBuilder<System.Threading.Tasks.VoidTaskResult>.AsyncStateMachineBox<StreamJsonRpc.JsonRpc.<HandleRpcAsync>d**165>.MoveNext(System.Threading.Thread threadPoolThread) Unknown
  > System.Private.CoreLib.dll!System.Runtime.CompilerServices.TaskAwaiter.OutputWaitEtwEvents.AnonymousMethod**12_0(System.Action innerContinuation, System.Threading.Tasks.Task innerTask) Unknown
  > System.Private.CoreLib.dll!System.Threading.Tasks.AwaitTaskContinuation.RunOrScheduleAction(System.Action action, bool allowInlining) Unknown
  > System.Private.CoreLib.dll!System.Threading.Tasks.Task.RunContinuations(object continuationObject) Unknown
  > StreamJsonRpc.dll!StreamJsonRpc.JsonRpc.DispatchIncomingRequestAsync(StreamJsonRpc.Protocol.JsonRpcRequest request) Unknown
  > [Resuming Async Method]
  > System.Private.CoreLib.dll!System.Threading.ExecutionContext.RunInternal(System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, object state) Unknown
  > System.Private.CoreLib.dll!System.Runtime.CompilerServices.AsyncTaskMethodBuilder<StreamJsonRpc.Protocol.JsonRpcMessage>.AsyncStateMachineBox<StreamJsonRpc.JsonRpc.<DispatchIncomingRequestAsync>d**158>.MoveNext(System.Threading.Thread threadPoolThread) Unknown
  > System.Private.CoreLib.dll!System.Runtime.CompilerServices.TaskAwaiter.OutputWaitEtwEvents.AnonymousMethod**12_0(System.Action innerContinuation, System.Threading.Tasks.Task innerTask) Unknown
  > System.Private.CoreLib.dll!System.Threading.Tasks.AwaitTaskContinuation.RunOrScheduleAction(System.Action action, bool allowInlining) Unknown
  > System.Private.CoreLib.dll!System.Threading.Tasks.Task.RunContinuations(object continuationObject) Unknown
  > StreamJsonRpc.dll!StreamJsonRpc.JsonRpc.DispatchRequestAsync(StreamJsonRpc.Protocol.JsonRpcRequest request, StreamJsonRpc.TargetMethod targetMethod, System.Threading.CancellationToken cancellationToken) Unknown
  > [Resuming Async Method]
  > System.Private.CoreLib.dll!System.Threading.ExecutionContext.RunInternal(System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, object state) Unknown
  > System.Private.CoreLib.dll!System.Runtime.CompilerServices.TaskAwaiter.OutputWaitEtwEvents.AnonymousMethod\_\_12_0(System.Action innerContinuation, System.Threading.Tasks.Task innerTask) Unknown
  > System.Private.CoreLib.dll!System.Threading.Tasks.AwaitTaskContinuation.System.Threading.IThreadPoolWorkItem.Execute() Unknown
  > System.Private.CoreLib.dll!System.Threading.ThreadPoolWorkQueue.DispatchWorkItem(object workItem, System.Threading.Thread currentThread) Unknown
  > System.Private.CoreLib.dll!System.Threading.ThreadPoolWorkQueue.Dispatch() Unknown
  > System.Private.CoreLib.dll!System.Threading.PortableThreadPool.WorkerThread.WorkerThreadStart() Unknown
  > System.Private.CoreLib.dll!System.Threading.Thread.StartHelper.RunWorker() Unknown

Does this work when demo console is retargeted to NETFX?

• Yes, when I target DemoConsole to NETFX, the "(none)" message still appears normally, just as described in the original issue.

[Tanya-Solyanik]

InProc designer will be closer to our demo console, please experiment with it as well.