delegate void handler();
interface iface {
        event handler theevent;
}

public class foo: iface {
}

--------------
Mono C# compiler version 1.1.9.1

foo.cs(6,14): error CS0535: `foo' does not implement interface member `iface.theevent'
foo.cs(3,16):: `iface.add_theevent', name of symbol related to previous error
foo.cs(6,14): error CS0535: `foo' does not implement interface member `iface.ve_theevent'
foo.cs(3,16):: `iface.remove_theevent', name of symbol related to previous error
Compilation failed: 2 error(s), 0 warnings

------------------
Visual C# .NET Compiler version 7.10.6310.4

foo.cs(6,14): error CS0535: 'foo' does not implement interface member

        'iface.theevent'

foo.cs(3,16): (Location of symbol related to previous error)