Explicit C# interface implementation of interfaces that inherit from other interfaces

Question

Consider the following three interfaces:

interface IBaseInterface
{
    event EventHandler SomeEvent;
}

interface IInterface1 : IBaseInterface
{
    ...
}

interface IInterface2 : IBaseInterface
{
    ...
}

Now consider the following class that implements both IInterface1 and IInterface 2:

class Foo : IInterface1, IInterface2
{
    event EventHandler IInterface1.SomeEvent
    {
        add { ... }
        remove { ... }
    }

    event EventHandler IInterface2.SomeEvent
    {
        add { ... }
        remove { ... }
    }
}

This results in an error because SomeEvent is not part of IInterface1 or IInterface2, it is part of IBaseInterface.

How can the class Foo implement both IInterface1 and IInterface2?

Answer 1

SomeEvent isn't part of IInterface1 or IInterface2, its a part of IBaseInterface.

class Foo : IInterface1, IInterface2
{
    event EventHandler IBaseInterface.SomeEvent {
        add { ... }
        remove { ... }
    }
}

Answer 2

interface IBaseInterface
{
event EventHandler SomeEvent;
}

interface IInterface1 : IBaseInterface
{
event EventHandler SomeEvent; }

interface IInterface2 : IBaseInterface
{
event EventHandler SomeEvent; }

class Foo : IInterface1, IInterface2
{
public event EventHandler SomeEvent { add { } remove { } }

 event EventHandler IInterface1.SomeEvent 
 {
     add { }
     remove { }
 }


 event EventHandler IInterface2.SomeEvent
 {
     add { }
     remove { }
 }

}