Compiler error CS0629

Conditional member 'member' cannot implement interface member 'base class member' in type 'Type Name'

The Conditional attribute cannot be used on the implementation of an interface.

The following sample generates CS0629:

// CS0629.cs  
interface MyInterface  
{  
   void MyMethod();  
}  
  
public class MyClass : MyInterface  
{  
   [System.Diagnostics.Conditional("debug")]  
   public void MyMethod()    // CS0629, remove the Conditional attribute  
   {  
   }  
  
   public static void Main()  
   {  
   }  
}