Compiler Error CS0424

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'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