Designer OOP Debugging

[amaitland]

Do you have any guidance on debugging the designer?

I get a The connection to the server has been lost dialog (be nice to have a meaningful error message here, the Winforms OOP Designer has terminated unexpectedly or something meaningful).

There's no information in the dialog, no stack trace. No errors in the event viewer.

Basic steps to reproduce:

• Open form in designer
• Drag a ChromiumWebBrowser instance from the toolbox
• Click save button
• Crash occurs.

https://github.com/cefsharp/CefSharp/tree/winforms/oopdesigner

(If someone would actually like to debug this then please let me know and I'll provide more detail)

Background

CefSharp project provides a WinForms implementation with a ultra minimalist designer (basically so you can add the control via the toolbox). CefSharp is build using VC++ and has many unmangaed dependencies. For the classic Designer I've always avoided making any calls that would attempt to load the VC++ dll.

Basically I need a stack trace to know what caused the exception.

[RussKie]

The OOP designer is a closed source, and while technically you can attach a debugger to the DesignToolsServer.exe you unlikely get far.
I am currently working on a diagnostics initiative but it will go only so far. Please check this guide https://github.com/dotnet/winforms/blob/main/docs/designer/troubleshooting.md.

The connection to the server has been lost is coming from the client when the server unexpectedly stops (e.g., crashes). If the logs don't provide any meaningful error (which can be fixed on your end), then please submit a VS Feedback issue and we'll investigate. Please post a link here, if you do.

If you're trying to get your control to work in the OOP designer, then you'll need to use https://www.nuget.org/packages/Microsoft.WinForms.Designer.SDK/. @KlausLoeffelmann is currently working on the docs and samples.
Please check out https://devblogs.microsoft.com/dotnet/state-of-the-windows-forms-designer-for-net-applications/ as well.

[amaitland]

For what it's worth there's also an exception when I chose not to save the form after it crashes.

[13:26:49.7640085] [CefSharp.WinForms.Example.netcore]: Disposing ServerProcess.
[13:43:59.9835203] Cannot update selection in server process as Session is not connected.
[13:44:00.0054020] Exception occurred while disposing VSDesignSurface
                   System.ObjectDisposedException: Cannot access a disposed object.
                   Object name: 'IServiceContainer'.
                      at System.ComponentModel.Design.DesignerHost.System.ComponentModel.Design.IServiceContainer.RemoveService(Type serviceType)
                      at Microsoft.WinForms.DesignTools.Client.Designers.ToolStrips.ClientToolStripService`1.Dispose(Boolean disposing)
                      at Microsoft.WinForms.Utilities.Shared.DisposableObject.DisposeIfNeeded(Boolean disposing)
                      at Microsoft.WinForms.Utilities.Shared.DisposableObject.Dispose()
                      at System.ComponentModel.Design.ServiceContainer.Dispose(Boolean disposing)
                      at System.ComponentModel.Design.DesignSurface.Dispose(Boolean disposing)
                      at Microsoft.VisualStudio.WinForms.VSDesignSurface.Dispose(Boolean disposing)

Quick search didn't show an open issue in your issue tracker.

[RussKie]

Didn't take me long to realise that was what had happened. I'd still advocate for a meaningful error message to be added.

From a usability point of view it would be great if the stack trace for the exception that occurred in the design process could be populated in the designer error within visual studio. There is no stack trace or error line information available for this error. is all I get currently.

Thank you for the feedback, I agree the WSOD page needs some attention. I'll add your suggestion to our backlog.

[EDIT] Raised in https://github.com/dotnet/winforms-designer/issues/4156 (internal only).

[RussKie]

For what it's worth there's also an exception when I chose not to save the form after it crashes.

[13:26:49.7640085] [CefSharp.WinForms.Example.netcore]: Disposing ServerProcess.
[13:43:59.9835203] Cannot update selection in server process as Session is not connected.
[13:44:00.0054020] Exception occurred while disposing VSDesignSurface
                   System.ObjectDisposedException: Cannot access a disposed object.
                   Object name: 'IServiceContainer'.
                      at System.ComponentModel.Design.DesignerHost.System.ComponentModel.Design.IServiceContainer.RemoveService(Type serviceType)
                      at Microsoft.WinForms.DesignTools.Client.Designers.ToolStrips.ClientToolStripService`1.Dispose(Boolean disposing)
                      at Microsoft.WinForms.Utilities.Shared.DisposableObject.DisposeIfNeeded(Boolean disposing)
                      at Microsoft.WinForms.Utilities.Shared.DisposableObject.Dispose()
                      at System.ComponentModel.Design.ServiceContainer.Dispose(Boolean disposing)
                      at System.ComponentModel.Design.DesignSurface.Dispose(Boolean disposing)
                      at Microsoft.VisualStudio.WinForms.VSDesignSurface.Dispose(Boolean disposing)

Great, this definitely helps to establish the context.
This types of issues need to be raised via VS Feedback, which collects additional information (such as screenshots, memory dumps, stack traces, assembly versions, etc.) that can help us to investigate the issue. Please post the link to the VS Feedback issue here, so that our team can track it.

Quick search didn't show an open issue in your issue tracker.

This repo is only for the runtime aspects of Windows Forms, i.e. the code that runs a Windows Forms app. The designer repo, where we track issues, is non-public.

[RussKie]

I should have asked before, what version of VS are you using?

[amaitland]

Microsoft Visual Studio Community 2022 (64-bit) - Current
Version 17.1.0