I have an interface defined in an IDL file that I would like to use in C#. Is there a way to convert the IDL to something usable in C#?
One way is to run MIDL
on the IDL to create a type library (.tlb). This requires a library
block in the IDL. Once you have the .tlb, you can run tlbimp.exe
on it to get a C# definition/Interop DLL.