This documentation is archived and is not being maintained.

Compiler Error CS0011 

Error Message

The base class or interface 'class' in assembly 'assembly' referenced by type 'type' could not be resolved

A class that was imported from a file with /reference, is derived from a class or implements an interface that is not found. This can occur if a required DLL is not also included in the compilation with /reference.

For more information, see Add Reference Dialog Box and /reference (Import Metadata) (C# Compiler Options).

Example

// CS0011_1.cs
// compile with: /target:library

public class Outer 
{
   public class B { }
}

The second file creates a DLL that defines a class C that is derived from the class B that was created in the previous example.

// CS0011_2.cs
// compile with: /target:library /reference:CS0011_1.dll
// post-build command: del /f CS0011_1.dll
public class C : Outer.B {}

The third file replaces the DLL created by the first step, and omits the definition of the inner class B.

// CS0011_3.cs
// compile with: /target:library /out:cs0011_1.dll
public class Outer {}

Finally, the fourth file references the class C defined in the second example, which is derived from class B, and which is now missing.

The following sample generates CS0011.

// CS0011_4.cs
// compile with: /reference:CS0011_1.dll /reference:CS0011_2.dll
// CS0011 expected

class M
{
   public static void Main()
   {
      C c = new C();
   }
}

See Also

Show: