Question

I want to know the difference between using Delegate Methods and using General Methods[without Delegates].

For Example :

---

With Delegate :

delegate void DelMethod(string str);

static void Method(string str)
{
    Debug.WriteLine(str);
}

Usage :

DelMethod dm = new DelMethod(Method);
dm(string);

---

And Without Delegate :

static void Method(string str)
{
    Debug.WriteLine(str);
}

Usage :

Method(string)

---

What are the differences of these two??

The method without delegate is smaller and easy. But I find coders using delegated Methods frequently.

What is the reason behind this??

Answer 1

Delegates are for another situation. Imagine, that you have a class which should answer for something from another class, but you know nothing about the second class. In such situation you can do a Delegate in the first.

// class where you know something
class A
{
   //delegate for answer
   public Func<bool> AskForSomething { get; set; }

   public void DoSomething()
   {
      //some code
      if(AskForSomething())
      {
          //do something
      }
      else
      {
          //do something else
      }
   }
}

class B
{
   public void Test()
   {
      A a = new A();
      a.AskForSomething = new Func<bool>(Answer);
      a.DoSomething();
   }

   private bool Answer()
   {
       return true;
   } 
}

Class A knows nothing about class B, but it can call B’s methods and get it’s results. The Answer method in class B is private and class A can’t call it directly.

Read more in MSDN