Delegate and Method

I have a delegate and a method. what are the steps to call that method (give technical steps)

1. Create a delegate
2. Create a function matching the signature as per the delegate or vice-versa
3. Assign method to the delegate instance
4. Call delegate function

The entire code looks like,

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class Program { public delegate int MYDelegate(int x, int y); static void Main(string[] args) { MYDelegate d = AddNumbers; Console.WriteLine(d(20, 30).ToString()); Console.ReadLine(); } public static int AddNumbers(int a, int b) { return (a + b); } }

Implementing Singleton Design Pattern using C#

Hello friends,

All of you must be aware of what Singleton Design Pattern is. Just to define it in one line, It is a pattern which allows creation of one and only instance of a class. 

The practical scenario where you can go with this pattern is having a print job class instance, single running instance of an application etc. 

The best example is Google Talk desktop application.
Let us try to implement this pattern via C# code.

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using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace DesignPatternsDemo { public class SingletonClass { private SingletonClass() { } //Implementation #1 //static SingletonClass _instance = null; //public static SingletonClass GetInstance() //{ // if (_instance == null) // { // _instance = new SingletonClass(); // } // return _instance; //} //Implementation #2 //Be aware that in a multithreaded program, different threads could try //to instantiate a class simultaneously. For this reason, a Singleton //implementation that relies on an if statement to check whether the //instance is null will not be thread-safe. Do not use code like that! static readonly SingletonClass _instance = new SingletonClass(); public static SingletonClass GetInstance { get { return _instance; } } public string GetWelcomeMessage() { return "Welcome to the Singleton world!! "; } } }

The Singleton class above will be instantiated only once.
When the GetInstance is called, it will return the statically created instance of the class.