Question

What’s the point of a public explicit interface and how does this differ from private?

interface IYer
{
    void Hello();
}

interface INer
{
    void Hello();
}

class MyClass : IYer, INer
{
    public void IYer.Hello()
    {
        throw new NotImplementedException();
    }

    public void INer.Hello()
    {
        throw new NotImplementedException();
    }
}

Answer 1

I’m not going to address the code above, which I believe has errors pointed out by others, but I’ll answer the question itself.

1. With explicit interface implementation, you can support multiple interfaces that have conflicting names.
2. You avoid emphasizing the availability of an interface to clients, when the interface isn’t important to most consumers of that class. This is because most languages in the Dotnet framework will require an explicit cast to the interface before you can use methods from explicitly implemented interfaces.
3. Less important, but I’ve used them to prevent accidental use of a method or property accessor: Using Explicit Interfaces to prevent accidental modification of properties in C#