Compiler Error CS0424
'class': a class with the ComImport attribute cannot specify a base class
Specifying the ComImportAttribute attribute implies that the implementation for the class is to be imported from a COM module. Additional methods or fields inherited from the base class are not allowed to be added to the implementation defined in the COM module.
The following sample generates CS0424:
// CS0424.cs
// compile with: /target:library
using System.Runtime.InteropServices;
public class A {}
[ ComImport, Guid("7ab770c7-0e23-4d7a-8aa2-19bfad479829") ]
class B : A {} // CS0424 error