// Construct 2 delegate objects that refer to the 
// same target/method
Feedback fb1 = new Feedback(FeedbackToConsole);
Feedback fb2 = new Feedback(FeedbackToConsole);

// Even though fb1 and fb2 refer to two different objects 
// internally, they both refer to the same callback 
// target/method.
Console.WriteLine(fb1.Equals(fb2));   // Displays "True"

// Construct 2 delegate objects that refer to the same target/method
Feedback fb1 = new Feedback(FeedbackToConsole);
Feedback fb2 = new Feedback(FeedbackToConsole);

// Even though fb1 and fb2 refer to two different objects internally,
// they both refer to the same callback target/method.
Console.WriteLine(fb1 == fb2);   // Displays "True"

class System.Delegate {
   // Combines the chains represented by head & tail, head is returned
   // (NOTE: head will be the last delegate called)
   public static Delegate Combine(Delegate tail, Delegate head);

   // Creates a chain represented by the array of delegates
   // (NOTE: entry 0 is the head and will be the last delegate called)
   public static Delegate Combine(Delegate[] delegateArray);

   // Removes a delegate matching value’s Target/Method from the chain.
   // The new head is returned and will be the last delegate called
   public static Delegate Remove(Delegate source, Delegate value);
}

Feedback fb1 = new Feedback(FeedbackToConsole);
Feedback fb2 = new Feedback(FeedbackToMsgBox);
Feedback fbChain = (Feedback) Delegate.Combine(fb1, fb2);
// The left side of Figure?1 shows what the 
// chain looks like after the previous code executes

App appobj = new App();
Feedback fb3 = new Feedback(appobj.FeedbackToStream);
fbChain = (Feedback) Delegate.Combine(fbChain, fb3);

Feedback[] fbArray = new Feedback[3];
fbArray[0] = new Feedback(FeedbackToConsole);
fbArray[1] = new Feedback(FeedbackToMsgBox);
App appobj = new App();
fbArray[2] = new Feedback(appobj.FeedbackToStream);

Feedback fbChain = Delegate.Combine(fbArray);

public delegate void     
   Feedback(
   Object value, Int32 item, Int32 numItems);

class Feedback : MulticastDelegate {
   public void virtual Invoke(
      Object value, Int32 item, Int32 numItems) {

      // If there are any delegates in the chain that
      // should be called first, call them
      if (_prev != null) _prev.Invoke(value, item, numItems);

      // Call our callback method on the specified target object
     _target.methodPtr(value, item, numItems);
   }
}

public delegate Int32 Feedback(
   Object value, Int32 item, Int32 numItems);

class Feedback : MulticastDelegate {
   public Int32 virtual Invoke(
      Object value, Int32 item, Int32 numItems) {

      // If there are any delegates in the chain that
      // should be called first, call them
      if (_prev != null) _prev.Invoke(value, item, numItems);

// Call our callback method on the specified target object 
   return _target.methodPtr(value, item, numItems);
   }
}

public class MulticastDelegate {
   // Creates a delegate array; each item is a clone from the chain
   // (NOTE: entry 0 is the tail, which would normally be called first)
   public virtual Delegate[] GetInvocationList();
}