What is Delegate ?

What is Delegate ? Delegates are a way to reference methods based on their signature and return type. It is also reffered as a type safe function pointers.Delegates are created at run time.It Used to call a method asynchronously. Declaration:                public delegate type_of_delegate delegate_name(); Example:               public delegate void SampleDelegate(string message); Sample Program : Delegate with Named method namespace DelegateSample {     public delegate void DisplayMessage(String sMessage);                         public partial class Form1 : Form     {         public Form1()         {             InitializeComponent();         }                             public void DispalyString(String sMessage)         {             MessageBox.Show(sMessage, "Information", MessageBoxButtons.OK, MessageBoxIcon.Information);         }                             private void btnDisplay_Click(object sender, EventArgs e)         {             try             {                 DisplayMessage oDisplay = DispalyString;                 oDisplay("Sample Delegate...");             }             catch (Exception Ex)             {                 throw (new Exception(Ex.Message));             }                     }     } } Delegate with Anonymous method         private void btnDisplay_Click(object sender, EventArgs e)         {             try             {                 // Delegate with Named method                 DisplayMessage oDisplay = DispalyString;                 oDisplay("Sample Delegate...");                               // Delegate with anonymous method                 DisplayMessage oDispAnonymous = delegate(String sMessage)                 {                     MessageBox.Show(sMessage, "Information", MessageBoxButtons.OK, MessageBoxIcon.Information);                 };                 oDispAnonymous("Delegate With Anonymous Method...");                                             oDisp("Delegate With Anonymous Method. Outside the function...");                           }             catch (Exception Ex)             {                 throw (new Exception(Ex.Message));             }                     }                       // Delegate with anonymous method                       DisplayMessage oDisp = delegate(String sMessage)         {             MessageBox.Show(sMessage, "Information", MessageBoxButtons.OK, MessageBoxIcon.Information);         }; Multicast Delegate             It is a Delegate which holds the reference of more than one methods.Th multicast delegates return type should be "void" Otherwise it will throw the exception. Sample Program : namespace DelegateSample {     public delegate void DisplayMessage();         public partial class Form1 : Form     {         public Form1()         {             InitializeComponent();         }             public void DispalyString1()         {             MessageBox.Show("Execute First...", "Information", MessageBoxButtons.OK, MessageBoxIcon.Information);         }             public void DispalyString2()         {             MessageBox.Show("Execute Second...", "Information", MessageBoxButtons.OK, MessageBoxIcon.Information);         }             private void btnDisplay_Click(object sender, EventArgs e)         {             try             {                 DisplayMessage oDisplay =new DisplayMessage(DispalyString1);                 // Add one more Method.                 oDisplay += new DisplayMessage(DispalyString2);                     oDisplay();                                 // To Remove the First Method.                 oDisplay -= new DisplayMessage(DispalyString1);                     oDisplay();                 }             catch (Exception Ex)             {                 throw (new Exception(Ex.Message));             }          }     } } conclusion              The delegate is one of the key concepts of C# and are very interesting aspects of the language.