Question

I have the following code:

// IMyInterface.cs

namespace InterfaceNamespace
{
    interface IMyInterface
    {
        void MethodToImplement();
    }
}

.

// InterfaceImplementer.cs
class InterfaceImplementer : IMyInterface
{
    void IMyInterface.MethodToImplement()
    {
        Console.WriteLine("MethodToImplement() called.");
    }
}

This code compiles just fine(why?). However when I try to use it:

// Main.cs

    static void Main()
    {
        InterfaceImplementer iImp = new InterfaceImplementer();
        iImp.MethodToImplement();
    }

I get:

InterfaceImplementer does not contain a definition for 'MethodToImplement'

i.e. MethodToImplement is not visible from outside. But if I do the following changes:

// InterfaceImplementer.cs
class InterfaceImplementer : IMyInterface
{

    public void MethodToImplement()
    {
        Console.WriteLine("MethodToImplement() called.");
    }
}

Then Main.cs also compiles fine. Why there is a difference between those two?

Answer 1

By implementing an interface explicitly, you’re creating a private method that can only be called by casting to the interface.