C # simple example of event proxy

Events and proxies are hard to understand. I have learned some examples from them. Delegate in C # And function pointers in C ++ are basically the same thing, C # implements the function pointer in the form of delegate. The difference is that delegate in C # is type-safe.

Example 1:

Namespace delegatetest
{
Public Delegate void mydelegate ();
Class Test
{
Static void main (string [] ARGs)
{
Changedevent chanevent = new changedevent ();
Eventlistener eventlis = new eventlistener (chanevent );
Chanevent. onchanged ();

Console. Read ();
}
}
// Define a class that contains event members. An event is triggered when a change occurs.
Public class changedevent
{
Public event mydelegate changed;
Public void onchanged ()
{
If (changed! = NULL)
Console. writeline ("trigger event :");

Changed ();
}

}

// Create a class containing the processing method
Class eventlistener
{
// It is used to save the objects passed from the parameter of the constructor culvert, mainly to unbind the event in the future
// Private changedevent CE;

Public eventlistener (changedevent CE)
{
// Ce = Ce;
Ce. Changed + = new mydelegate (dispmethod );
}
Private void dispmethod ()
{
Console. writeline ("this is called when the event fires .");

}

}
}

Example 2:

Namespace delegate2
{

Public Delegate void mydelegate ();
Class Test
{

Static void main (string [] ARGs)
{
Changedevent chanevent = new changedevent ();
A A = new ();
Chanevent. Changed + = new mydelegate (A. dispmethod );
Chanevent. onchanged ();

Console. Read ();
}
}
Class
{

Public void dispmethod ()
{
Console. writeline ("this is called when the event fires .");

}
}

// Define a class that contains event members. An event is triggered when a change occurs.
Public class changedevent
{
// Public Delegate void mydelegate ();

Public event mydelegate changed;
Public void onchanged ()
{
If (changed! = NULL)
{
Console. writeline ("trigger event :");

Changed ();
}
}

Example 3: Delegate with Parameters

Namespace consoleapplication1
{
// Define the delegate
Public Delegate bool compareint (int A, int B );
Public class mycompare
{
Public static bool showresult (int x, int y)
{
Bool Index = x> Y? True: false;
Return Index;
}

}
Class Program
{

Static void main (string [] ARGs)
{
Compareint mydelegate = new compareint (mycompare. showresult );
Int A = 20;
Int B = 15;
Bool whobigger = mydelegate (A, B );
Console. writeline ("A> B? : "+ Whobigger );
Console. Read ();
}
}
}