It is a team project in my university. I need to extends project which have
been written by C# before.
The problem have been solved.
Really thank you!!
If they are already compiled as Class Libraries, then just add a reference
to your VB.NET Project. If they have yet to be created but will be written
in C#, then just include the project in your solution. Set the compile
order to match the precedence, and that's about it.
I assume that the function is implemented as a method of a class defined
in a C# Class Library. If you are using VB.NET Standard or VS.NET,
simply add a reference to the class library (see folder "References" in
the solution explorer). Then you can import the necessary namespaces
and use the classes and their methods.