C# Com

using System;
using System.Collections.Generic;
using System.Text;
using System.Runtime.InteropServices;

namespace ComInterOpExample
{
    [Guid("69C85C8D-DBEB-4d85-83A7-7E5077AD11BA")]
    [InterfaceType(ComInterfaceType.InterfaceIsIDispatch)]
    public interface iInterface
    {
        [DispId(1)] int PerformAddition(int a, int b);
        [DispId(2)] int PerformDeletion(int a, int b);
    }
    
    [Guid("0C216A19-E1B7-4b05-86D3-4C516BDDC041")]
    [ClassInterface(ClassInterfaceType.None)]
    [ProgId("ComInterOpClass")]  
    public class ComInterOpClass:iInterface
    {
        #region iInterface Members

        public int PerformAddition(int a, int b)
        {
           // throw new Exception("The method or operation is not implemented.");
            try
            {
                return a + b;
            }
            catch
            {
                return 0;
            }
        }

        public int PerformDeletion(int a, int b)
        {
            //throw new Exception("The method or operation is not implemented.");
            try
            {
                return a - b;
            }
            catch
            {
                return 0;
            }
        }

        #endregion
    }
}