Hi Tomasz,

This is a good question. In fact, it is the difference between C# and
VB.NET compilers.

In C#, when you fail to implement an interface, the compiler will
automatically look for a method with the same name as the method in the
interface and map it to the method implementation. In this case, since
there is an m1() method in c1, it will use this method to implement i1.m1().

However, this is not available in VB.NET compiler. That's why a compile
error is generated.

If anything is unclear, please feel free to let me know.

Kevin Yu
Microsoft Online Community Support

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rights.)

The VB conversion is:

'// C# version
'   class c1 {
'      public virtual void m1() {
'      }
'   }

'   class c2 : c1, i1 {
'   }

'   public interface i1 {
'      void m1();
'   }

' VB version
Class c1
   Public Overridable Sub m1()
   End Sub
End Class

Class c2
   Inherits c1
   Implements i1

   Public Sub m11() Implements i1.m1
       MyBase.m1()
   End Sub

End Class

Public Interface i1
   Sub m1()
End Interface

The real problem with this is that in VB, interfaces cannot contain default
code.  If it needs to, I would implement the classes as follows:

Class c1
   Public Overridable Sub m1()
       ' Default implementation of m1
   End Sub
End Class

Class c2
   Inherits c1

   ' To hide the underlying m1 implementation
   ' Public Shadows Sub m1()
   ' End Sub

   ' To extend the underlying my implementation.
   ' Public Overrides Sub m1()
   ' End Sub
End Class

Mike.