Submitting code from a C# cell using CSharpKernel.SubmitCodeAsync(string code) doesn't work properly

[Lawlzee]

Describe the bug

When submitting code from a C# cell, dot net interactive cannot find the submitted code. On the other hand, the submitted code is available in the IntelliSense.

Example

#!csharp

using Microsoft.DotNet.Interactive;
using Microsoft.DotNet.Interactive.CSharp;

CSharpKernel kernel  = (CSharpKernel)KernelInvocationContext.Current.HandlingKernel.FindKernel("csharp");
await kernel.SubmitCodeAsync("public class TestClass { public int A { get; set; } }");

#!csharp
//IntelliSense can see "TestClass", but dot net interactive can't
TestClass a = new TestClass();

Please complete the following:

Which version of .NET Interactive are you using? There are a few ways to find this out:

• In a notebook, run the #!about magic command.

.NET Interactive

© 2020 Microsoft Corporation

Version: 1.0.225503+3174511575ce656cd699fc7978d7c9a8ecd4353c

Build date: 2021-05-08T13:04:58.4839798Z

https://github.com/dotnet/interactive

• At the command line, run dotnet interactive --version.
  1.0.222801+f2ff13b19c29823ac625c235db4ee2343954cc87

• OS
  • Windows 10
  • macOS
  • Linux (Please specify distro)
  • iOS
  • Android
• Browser
  • Chrome
  • Edge
  • Firefox
  • Safari
• Frontend
  • Jupyter Notebook
  • Jupyter Lab
  • nteract
  • Visual Studio Code
  • Visual Studio Code Insiders
  • Other (please specify)

Screenshots

If applicable, add screenshots to help explain your problem.

[Lawlzee]

I ended up fixing my problem by simply calling kernel.DeferCommand(new SubmitCode(code)); instead.

[jonsequitur]

When submitting code to a kernel using that same kernel, using DeferCommand is the only supported approach.