Since .NET is .NET regardless of the language used you can use any .NET DLL in any .NET language (as long as the .NET versions are compatible that is). So you'll just have to add a reference to the Microsoft.VisualBasic.dll to your project and add a using clause to your code:
using Microsoft.VisualBasic.FileIO;
Now you are ready to use the
SpecialDirectories Class[
^] from your C# code.
Regards,
Manfred