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C# in a Nutshell, Second Edition
book

C# in a Nutshell, Second Edition

by Peter Drayton, Ben Albahari, Ted Neward
August 2003
Intermediate to advanced content levelIntermediate to advanced
928 pages
32h 1m
English
O'Reilly Media, Inc.
Content preview from C# in a Nutshell, Second Edition

Delegates Versus Interfaces

A problem that can be solved with a delegate can also be solved with an interface. For instance, the following explains how to solve our filter problem using an IFilter interface:

using System;
interface IFilter {
   bool Filter(string s);
}
class Test {
  class FirstHalfOfAlphabetFilter : IFilter {
    public bool Filter(string s) {
      return ("N".CompareTo(s) > 0);
    }      
  }
  static void Main( ) {
    FirstHalfOfAlphabetFilter f = new FirstHalfOfAlphabetFilter( );
    Display(new string [ ] {"Ant", "Lion", "Yak"}, f);
  }
  static void Display(string[ ] names, IFilter f) {
    int count = 0;
    foreach (string s in names)
      if (f.Filter(s))
        Console.WriteLine("Item {0} is {1}", count++, s);
  }
}

In this case, the problem is slightly more elegantly handled with a delegate, but generally delegates are best used for event handling.

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Publisher Resources

ISBN: 0596005261Catalog PageErrata