Delegates Program

Question

I made a very simple program of Delegates. I have no idea why is it showing error, even though I compared it with the one given in MSDN library, its same like the one in MSDN, still not getting compiled..the error says- "The name 'Add' does not exist in the current context "and same for the other method.. Subtract. Please help me find what is the problem..

namespace DelegatePrac
{   
   public delegate void One(int a, int b); 
    public class Some
     {
  static void Add(int a, int b)
       { 
      int c = a + b;    Console.WriteLine("{0}",c);
       }
       static void Subtract(int a, int b)
       { int c = a - b;  Console.WriteLine("{0}",c);
       }

    }

    class Program
    {
        static void Main(string[] args)
        {
            One o1,o2;
            o1 = Add;//gives error here
            o2 = Subtract;//and here!!
            o1(33,44);
            o2(45, 15);
         Console.ReadLine();
        }
    }
}

I was following this link- http://msdn.microsoft.com/en-us/library/ms173175.aspx

Thanks

Answer 1

You should see a compiler message:

The name 'Add' does not exist in the current context

which tells you that it has no clue which Add method you are talking about; Add is a static method in Some - so you need:

o1 = Some.Add;
o2 = Some.Subtract;

static methods aren't globally available; you can access static methods from the current type (and from base-types) via just their name, but if it is an unrelated type you need to qualify it with the declaring-type.

At this point it will give you a compiler error:

'DelegatePrac.Some.Add(int, int)' is inaccessible due to its protection level

which hints that it is a private method; so add public (or internal) to them:

public static void Add(int a, int b) {...}