We could not able to perform design time debugging in NetCore Windows Forms. We have tried to perform debugging as like we perform for .NetFramework but our source code cannot be able to debug at design time. We have followed the below steps. Set the break point in our custom control constructor. Set the start up project as “devenv.exe”. On running the application it shows another VisualStudio instance where we will select the project that we need to debug. Then on opening the designer and adding the custom control from toolbox. Expected result: The Break point set at out custom control constructor should hit. Observed result: The break point hit properly in .Net Framework project. But not for Net core project. Please let us know if we need to enable any other operations to debug for NET core project. Note: We have enabled preview feature for NetCore.

Windows Forms Designer debugging in NetCore

Senthil Kumaran Rajan 1

We could not able to perform design time debugging in NetCore Windows Forms.

We have tried to perform debugging as like we perform for .NetFramework but our source code cannot be able to debug at design time. We have followed the below steps.

Set the break point in our custom control constructor.
Set the start up project as “devenv.exe”.
On running the application it shows another VisualStudio instance where we will select the project that we need to debug.
Then on opening the designer and adding the custom control from toolbox.

Expected result:
The Break point set at out custom control constructor should hit.

Observed result:
The break point hit properly in .Net Framework project. But not for Net core project.

Please let us know if we need to enable any other operations to debug for NET core project.

Note:
We have enabled preview feature for NetCore.

Lex Li (Microsoft) 5,582 Reputation points Microsoft Employee

2021-05-07T16:23:51.207+00:00

The .NET Core designer is running in a separate process, not devenv.exe. So you should attach to that separate process instead.
Karen Payne MVP 35,426 Reputation points

2021-05-08T11:51:06.597+00:00

Have you considered installing a non-preview (not talking about form designer) version of Visual Studio?
Tianyu Sun-MSFT 30,811 Reputation points Microsoft Vendor

2021-05-10T03:27:45.08+00:00

Hi @Senthil Kumaran Rajan , welcome to Microsoft Q&A forum. Have you also tried to update VS 2019 to the latest version, and repair VS 2019? If you create a new simple custom control and create a new .NET WinForm project to debug, will this newly created project work?
Tianyu Sun-MSFT 30,811 Reputation points Microsoft Vendor

2021-06-02T08:29:45.927+00:00

Hi @Senthil Kumaran Rajan , do you have any update? Have you also tried check the Enable native code debugging option in Properties > Debug > Debugger engines > Enable native code debugging?

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Windows Forms Designer debugging in NetCore

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