Implementing interfaces with static members

[josephmoresena]

I am trying to implement an interface created in a C# assembly in .NET 8, which has both static virtual and abstract members. However, it's not possible to implement this interface in a Visual Basic class because all interface implementation methods have to be instance methods, and when I try to compile, it indicates that the method does not match the interface.

[Nukepayload2]

The ability of consuming C# code in VB is already broken since C# 7.2. Here's a list of interoperability issues of calling C# library with VB (found in my projects):

• Use ref struct (Span(Of T), Utf8JsonReader)
• Use ref readonly returns (ReadOnlySpan(Of T).Item)
• Override methods that have in parameters
• Override ref readonly parameters
• Override methods that have covariance returns
• Use fixed buffers
• Consume members that have unmanaged constraint (ImageSharp, OpenCVSharp)
• Use unmanaged delegates
• Inherit record types
• Use or implement default interface members
• Implement IAsyncEnumerable
• Dispose IAsyncDisposable objects with Try ... Finally
• Implement async functions that has a return type requires a custom AsyncStateMachine (Parallel.ForEachAsync)
• Use a custom logger that requires custom string interpolation handlers
• Override methods with allows ref struct constraint
• Override init properties
• Use libraries that only have C# source generators (Mvvm community toolkit, LibraryImportAttribute, AOT Json serializer, AOT regex)

[paul1956]

@Nukepayload2 are these is the Roslyn Repo? Does on the team actually look here anymore? Give the goal of keeping VB compatible with C# libraries all of these should be bugs.

[aarondglover]

@Nukepayload2 are these is the Roslyn Repo? Does on the team actually look here anymore? Give the goal of keeping VB compatible with C# libraries all of these should be bugs.

Its just not going to happen @paul1956 :(

[paul1956]

@Nukepayload2 They are in the process of fixing the "constraint" issue, a major compatibility issue with VB consuming C# Libraries. and it's a very big change.

If people report compatibility issues using VS Feedback NOT HERE and up-vote them in VS Feedback they seem to be getting attention.

On another positive note I with the help of the testing team have been updating and reimplementing WinForms VB Runtime using more modern VB and Async and improving tests coverage to as close to 100% as possible without using "mock" which I don't understand.

I have lost track of the total number of PR's merged but its significant, in the process bugs have been uncovered and fixes especially around Clipboard. And .Net 9 includes a significant start are Dark Mode with fill VB support.

There are 180 new tests written in VB and at least double that number written in C# to test VB Runtime.

[Nukepayload2]

@paul1956

They are in the process of fixing the "constraint" issue

This is a good news. We can finally use OpenCVSharp and ImageSharp.

If people report compatibility issues using VS Feedback NOT HERE and up-vote them in VS Feedback they seem to be getting attention.

I've created or upvoted some feedbacks before. But they were marked as Closed - Lower Priority. I'll try to create more VB/C# interop feedbacks that don't require new syntaxes to resolve.

[paul1956]

Need to be a campaign to upvote.

[AnthonyDGreen]

The unmanaged constraint fix for those interested.