Explicit interface implementation cannot be virtual

Question

For the record, I\'ve already seen this connect item but I can\'t really understand what would be the problem in supporting this.

Say I have the following code:

Answer 1

I think the reason can be simply shown in following example. Consider this code:

public interface IInterfaceA
{
    void Method();
}

public interface IInterfaceB
{
    void Method();
}

public class Base : IInterfaceA, IInterfaceB
{
    virtual void IInterfaceA.Method()
    {
       ...
    }

    virtual void IInterfaceB.Method()
    {
       ...
    }
}

public class Derived : Base
{
    public override void Method()
    {
        // Will this override IInterfaceA or IInterfaceB implementation???
    }
}

So, in short, if you explicitly implement multiple interfaces with the same method signature your derived classes will not know which base method you want to override.