Question

might someone have a quick answer for me…

in the following entirely useless code, under ‘class DuplicateInterfaceClass : MyInterface1, MyInterface2’.

Why can’t I explicitly write “public string MyInterface2.P()”?

yet “public string P()” and “string MyInterface2.P()” work.

I understand that all interface methods (properties, etc.) are implicitly “public” by default, but my attempt to be explicit in the inheriting class results in an “error CS0106: The modifier ‘public’ is not valid for this item”.

using System;

interface MyInterface1
{
    void DuplicateMethod();

    // interface property
    string P
    {   get;    }
}

interface MyInterface2
{
    void DuplicateMethod();

    // function ambiguous with MyInterface1's property
    string P();
}

// must implement all inherited interface methods
class DuplicateInterfaceClass : MyInterface1, MyInterface2
{
    public void DuplicateMethod()
    {
        Console.WriteLine("DuplicateInterfaceClass.DuplicateMethod");
    }

    // MyInterface1 property
    string MyInterface1.P
    {   get
        {   return ("DuplicateInterfaceClass.P property");  }
    }

    // MyInterface2 method
    // why? public string P()...and not public string MyInterface2.P()?
    string MyInterface2.P()
    {   return ("DuplicateInterfaceClass.P()"); }

}

class InterfaceTest
{
    static void Main()
    {
        DuplicateInterfaceClass test = new DuplicateInterfaceClass();       
        test.DuplicateMethod();     

        MyInterface1 i1 = (MyInterface1)test;
        Console.WriteLine(i1.P);

        MyInterface2 i2 = (MyInterface2)test;
        Console.WriteLine(i2.P());
    }
}

Answer 1

I have this explicit message from Resharper :
“The modifier ‘public’ is not valid for explicit interface implementation.”

But you can do that :

class DuplicateInterfaceClass : MyInterface1, MyInterface2
{
 public void DuplicateMethod()
 {
  Console.WriteLine("DuplicateInterfaceClass.DuplicateMethod");
 }

 string MyInterface1.P
 { get { return "DuplicateInterfaceClass.P"; } }

 string MyInterface2.P()
 { return "DuplicateInterfaceClass.P()"; }

 public string P()
 { return ((MyInterface2)this).P(); }
}