Class inheriting from several Interfaces having sa

问题:

Say, I have three interfaces:

public interface I1
{
    void XYZ();
}
public interface I2
{
    void XYZ();
}
public interface I3
{
    void XYZ();
}

A class inheriting from these three interfaces:

class ABC: I1,I2, I3
{
      // method definitions
}

Questions:

• If I implement like this:

  class ABC: I1,I2, I3 {

      public void XYZ()
      {
          MessageBox.Show("WOW");
      }
  

  }

It compiles well and runs well too! Does it mean this single method implementation is sufficient for inheriting all the three Interfaces?

• How can I implement the method of all the three interfaces and CALL THEM? Something Like this:

  ABC abc = new ABC();
  abc.XYZ(); // for I1 ?
  abc.XYZ(); // for I2 ?
  abc.XYZ(); // for I3 ?
  

I know it can done using explicit implementation but I'm not able to call them. :(

回答1:

If you use explicit implementation, then you have to cast the object to the interface whose method you want to call:

class ABC: I1,I2, I3
{
    void I1.XYZ() { /* .... */ }
    void I2.XYZ() { /* .... */ }
    void I3.XYZ() { /* .... */ }
}

ABC abc = new ABC();
((I1) abc).XYZ(); // calls the I1 version
((I2) abc).XYZ(); // calls the I2 version

回答2:

You can call it. You just have to use a reference with the interface type:

I1 abc = new ABC();
abc.XYZ();

If you have:

ABC abc = new ABC();

you can do:

I1 abcI1 = abc;
abcI1.XYZ();

or:

((I1)abc).XYZ();

回答3:

During implementation in a class do not specify modifier o/w you will get compilation error, also specify the interface name to avoid ambiguity.You can try the code:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleCSharp
{
    class Program
    {
        static void Main(string[] args)
        {
            MyClass mclass = new MyClass();

            IA IAClass = (IA) mclass;
            IB IBClass = (IB)mclass;

            string test1 = IAClass.Foo();
            string test33 = IBClass.Foo();


            int inttest = IAClass.Foo2();
            string test2 = IBClass.Foo2();


            Console.ReadKey();
        }
    }
public class MyClass : IA, IB
{
    static MyClass()
    {
        Console.WriteLine("Public class having static constructor instantiated.");
    }
    string IA.Foo()
    {
        Console.WriteLine("IA interface Foo method implemented.");
        return ""; 
    }
    string IB.Foo()
    {
        Console.WriteLine("IB interface Foo method  having different implementation. ");
        return "";
    }

    int IA.Foo2()
    {
        Console.WriteLine("IA-Foo2 which retruns an integer.");
        return 0;
    }

    string IB.Foo2()
    {
        Console.WriteLine("IA-Foo2 which retruns an string.");
        return "";
    }
}

public interface IA
{
    string Foo(); //same return type
    int Foo2(); //different return tupe
}

public interface IB
{
    string Foo();
    string Foo2();
}

}