Could not load type 'System.Windows.Forms.MenuMerge' from assembly 'System.Windows.Forms, Version=5.0.7.0, Culture=neutral, PublicKeyToken=b77a5c561934e089'

Question

I upgrade my winform vb.net project from framework 4.7.2 to .net 5. It is compiling well. I got the runtime error "Could not load type 'System.Windows.Forms.MenuMerge' from assembly 'System.Windows.Forms, Version=5.0.7.0, Culture=neutral, PublicKeyToken=b77a5c561934e089'".

Thanks in advance for any help!

PS
Assembly System.Windows.Forms
C: \ Program Files \ dotnet \ packs \ Microsoft.WindowsDesktop.App.Ref \ 5.0.0 \ ref \ net5.0 \ System.Windows.Forms.dll

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Assembly System.Windows.Forms
Member of .NET Framework 2.0, .NET Framework 3.0, .NET Framework 3.5
C: \ Windows \ Microsoft.NET \ Framework \ v2.0.50727 \ System.Windows.Forms.dll

Answer 1

That type (as well as other obsolete WinForms types) has been removed from .NET Core in 3.1/5.0 time frame.

You can find the progress tracked in GitHub issues like this.

The solution, is not to use any obsolete items any more in your applications.

Answer 2

Hi @Zhen ,

Both MenuMerge and MenuItem are not supported in .net 5.
Use ToolStripMenuItem instead, which replaces the MenuItem control.

Hope it could be helpful.

Best Regards,
Xingyu Zhao
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