Compiler Error CS0263

Partial declarations of 'type' must not specify different base classes

When defining a type in partial declarations, specify the same base types in each of the partial declarations. For more information, see Partial Classes and Methods.

The following sample generates CS0263:

// CS0263.cs  
// compile with: /target:library  
class B1  
{  
}  
  
class B2  
{  
}  
partial class C : B1  // CS0263 – is the base class B1 or B2?  
{  
}  
  
partial class C : B2  
{  
}