Delegates - Illustrated C# 2005 - page 343

Delegate Example
The following code defines and uses a delegate with no parameters and no return value. Note
the following about the code:

￿Class Test defines two print functions.

￿Method Main creates an instance of the delegate and then adds three more methods.

￿ The program then invokes the delegate, which calls its methods.

￿ Note the test for the null delegate, before attempting to invoke it.

// Define a delegate with no return value and no parameters.
delegate void PrintFunction();

class Test
{
public void Print1()
{ Console.WriteLine("Print1 -- instance"); }

public static void Print2()
{ Console.WriteLine("Print2 -- static"); }
}

class Program
{
static void Main()
{
Test t = new Test(); // Create a test class instance.
PrintFunction pf; // Create a null delegate.

pf = t.Print1; // Instantiate and initialize the delegate.

// Add three more methods to the delegate.
pf += Test.Print2;
pf += t.Print1;
pf += Test.Print2;
// The delegate now contains four methods.
if( null != pf ) // Make sure the delegate has methods.
pf(); // Invoke the delegate.
else
Console.WriteLine("Delegate is empty");
}
}