1、声明一个委托类 public delegate SomethingChangedHandler(object sender,EventArgs e);
2、在你的类中声明一个事件绑定到该委托 public event SomethingChangedHandler Changed;
3、在相应的方法中触发此事件
public void ChangeSomething()
{
.................
Changed(this,new EventArgs); //触发事件
}
4、在调用者订阅事件
your class's instance.Changed+=new SomethingChangedHandler(你的方法名);
SAMPLE----from MSDN:namespace EventSample
{
using System;
using System.ComponentModel;
// Class that contains the data for
// the alarm event. Derives from System.EventArgs.
//
public class AlarmEventArgs : EventArgs
{
private readonly bool snoozePressed ;
private readonly int nrings;
//Constructor.
//
public AlarmEventArgs(bool snoozePressed, int nrings)
{
this.snoozePressed = snoozePressed;
this.nrings = nrings;
}
// The NumRings property returns the number of rings
// that the alarm clock has sounded when the alarm event
// is generated.
//
public int NumRings
{
get { return nrings;}
}
// The SnoozePressed property indicates whether the snooze
// button is pressed on the alarm when the alarm event is generated.
//
public bool SnoozePressed
{
get {return snoozePressed;}
}
// The AlarmText property that contains the wake-up message.
//
public string AlarmText
{
get
{
if (snoozePressed)
{
return ("Wake Up!!! Snooze time is over.");
}
else
{
return ("Wake Up!");
}
}
}
}
// Delegate declaration.
//
public delegate void AlarmEventHandler(object sender, AlarmEventArgs e);
// The Alarm class that raises the alarm event.
//
public class AlarmClock
{
private bool snoozePressed = false;
private int nrings = 0;
private bool stop = false;
// The Stop property indicates whether the
// alarm should be turned off.
//
public bool Stop
{
get {return stop;}
set {stop = value;}
}
// The SnoozePressed property indicates whether the snooze
// button is pressed on the alarm when the alarm event is generated.
//
public bool SnoozePressed
{
get {return snoozePressed;}
set {snoozePressed = value;}
}
// The event member that is of type AlarmEventHandler.
//
public event AlarmEventHandler Alarm; // The protected OnAlarm method raises the event by invoking
// the delegates. The sender is always this, the current instance
// of the class.
//
protected virtual void OnAlarm(AlarmEventArgs e)
{
if (Alarm != null)
{
// Invokes the delegates.
Alarm(this, e);
}
}
// This alarm clock does not have
// a user interface.
// To simulate the alarm mechanism it has a loop
// that raises the alarm event at every iteration
// with a time delay of 300 milliseconds,
// if snooze is not pressed. If snooze is pressed,
// the time delay is 1000 milliseconds.
//
public void Start()
{
for (;;)
{
nrings++;
if (stop)
{
break;
}
else if (snoozePressed)
{
System.Threading.Thread.Sleep(1000);
{
AlarmEventArgs e = new AlarmEventArgs(snoozePressed,
nrings);
OnAlarm(e);
}
}
else
{
System.Threading.Thread.Sleep(300);
AlarmEventArgs e = new AlarmEventArgs(snoozePressed,
nrings);
OnAlarm(e);
}
}
}
}
// The WakeMeUp class that has a method AlarmRang that handles the
// alarm event.
//
public class WakeMeUp
{
public void AlarmRang(object sender, AlarmEventArgs e)
{
Console.WriteLine(e.AlarmText +"\n");
if (!(e.SnoozePressed))
{
if (e.NumRings % 10 == 0)
{
Console.WriteLine(" Let alarm ring? Enter Y");
Console.WriteLine(" Press Snooze? Enter N");
Console.WriteLine(" Stop Alarm? Enter Q");
String input = Console.ReadLine();
if (input.Equals("Y") ||input.Equals("y")) return;
else if (input.Equals("N") || input.Equals("n"))
{
((AlarmClock)sender).SnoozePressed = true;
return;
}
else
{
((AlarmClock)sender).Stop = true;
return;
}
}
}
else
{
Console.WriteLine(" Let alarm ring? Enter Y");
Console.WriteLine(" Stop Alarm? Enter Q");
String input = Console.ReadLine();
if (input.Equals("Y") || input.Equals("y")) return;
else
{
((AlarmClock)sender).Stop = true;
return;
}
}
}
}
// The driver class that hooks up the event handling method of
// WakeMeUp to the alarm event of an Alarm object using a delegate.
// In a forms-based application, the driver class is the
// form.
//
public class AlarmDriver
{
public static void Main (string[] args)
{
// Instantiates the event receiver.
WakeMeUp w= new WakeMeUp();
// Instantiates the event source.
AlarmClock clock = new AlarmClock(); // Wires the AlarmRang method to the Alarm event.
clock.Alarm += new AlarmEventHandler(w.AlarmRang); clock.Start();
}
}
}
2、在你的类中声明一个事件绑定到该委托 public event SomethingChangedHandler Changed;
3、在相应的方法中触发此事件
public void ChangeSomething()
{
.................
Changed(this,new EventArgs); //触发事件
}
4、在调用者订阅事件
your class's instance.Changed+=new SomethingChangedHandler(你的方法名);
SAMPLE----from MSDN:namespace EventSample
{
using System;
using System.ComponentModel;
// Class that contains the data for
// the alarm event. Derives from System.EventArgs.
//
public class AlarmEventArgs : EventArgs
{
private readonly bool snoozePressed ;
private readonly int nrings;
//Constructor.
//
public AlarmEventArgs(bool snoozePressed, int nrings)
{
this.snoozePressed = snoozePressed;
this.nrings = nrings;
}
// The NumRings property returns the number of rings
// that the alarm clock has sounded when the alarm event
// is generated.
//
public int NumRings
{
get { return nrings;}
}
// The SnoozePressed property indicates whether the snooze
// button is pressed on the alarm when the alarm event is generated.
//
public bool SnoozePressed
{
get {return snoozePressed;}
}
// The AlarmText property that contains the wake-up message.
//
public string AlarmText
{
get
{
if (snoozePressed)
{
return ("Wake Up!!! Snooze time is over.");
}
else
{
return ("Wake Up!");
}
}
}
}
// Delegate declaration.
//
public delegate void AlarmEventHandler(object sender, AlarmEventArgs e);
// The Alarm class that raises the alarm event.
//
public class AlarmClock
{
private bool snoozePressed = false;
private int nrings = 0;
private bool stop = false;
// The Stop property indicates whether the
// alarm should be turned off.
//
public bool Stop
{
get {return stop;}
set {stop = value;}
}
// The SnoozePressed property indicates whether the snooze
// button is pressed on the alarm when the alarm event is generated.
//
public bool SnoozePressed
{
get {return snoozePressed;}
set {snoozePressed = value;}
}
// The event member that is of type AlarmEventHandler.
//
public event AlarmEventHandler Alarm; // The protected OnAlarm method raises the event by invoking
// the delegates. The sender is always this, the current instance
// of the class.
//
protected virtual void OnAlarm(AlarmEventArgs e)
{
if (Alarm != null)
{
// Invokes the delegates.
Alarm(this, e);
}
}
// This alarm clock does not have
// a user interface.
// To simulate the alarm mechanism it has a loop
// that raises the alarm event at every iteration
// with a time delay of 300 milliseconds,
// if snooze is not pressed. If snooze is pressed,
// the time delay is 1000 milliseconds.
//
public void Start()
{
for (;;)
{
nrings++;
if (stop)
{
break;
}
else if (snoozePressed)
{
System.Threading.Thread.Sleep(1000);
{
AlarmEventArgs e = new AlarmEventArgs(snoozePressed,
nrings);
OnAlarm(e);
}
}
else
{
System.Threading.Thread.Sleep(300);
AlarmEventArgs e = new AlarmEventArgs(snoozePressed,
nrings);
OnAlarm(e);
}
}
}
}
// The WakeMeUp class that has a method AlarmRang that handles the
// alarm event.
//
public class WakeMeUp
{
public void AlarmRang(object sender, AlarmEventArgs e)
{
Console.WriteLine(e.AlarmText +"\n");
if (!(e.SnoozePressed))
{
if (e.NumRings % 10 == 0)
{
Console.WriteLine(" Let alarm ring? Enter Y");
Console.WriteLine(" Press Snooze? Enter N");
Console.WriteLine(" Stop Alarm? Enter Q");
String input = Console.ReadLine();
if (input.Equals("Y") ||input.Equals("y")) return;
else if (input.Equals("N") || input.Equals("n"))
{
((AlarmClock)sender).SnoozePressed = true;
return;
}
else
{
((AlarmClock)sender).Stop = true;
return;
}
}
}
else
{
Console.WriteLine(" Let alarm ring? Enter Y");
Console.WriteLine(" Stop Alarm? Enter Q");
String input = Console.ReadLine();
if (input.Equals("Y") || input.Equals("y")) return;
else
{
((AlarmClock)sender).Stop = true;
return;
}
}
}
}
// The driver class that hooks up the event handling method of
// WakeMeUp to the alarm event of an Alarm object using a delegate.
// In a forms-based application, the driver class is the
// form.
//
public class AlarmDriver
{
public static void Main (string[] args)
{
// Instantiates the event receiver.
WakeMeUp w= new WakeMeUp();
// Instantiates the event source.
AlarmClock clock = new AlarmClock(); // Wires the AlarmRang method to the Alarm event.
clock.Alarm += new AlarmEventHandler(w.AlarmRang); clock.Start();
}
}
}
{
private string _text;
public string Text {
get {
return _text;
}
set {
if( _text!=value&&_textChanged!=null )
{
_text=value;
_textChanged( this,EventArgs.Empty ); //如果文本改动,则触发TextChanged事件
}
else
_text=value;
}
} private event EventHandler _textChanged;
public event EventHandler TextChanged
{
add {
_textChanged += value;
}
remove {
_textChanged -= value;
}
}
}public class Test
{
public Combox _myBox = new Combox;
public Test()
{
_myBox.TextChanged += new EventHandler( this.OnBoxTextChanged );//注册事件
}
void OnBoxTextChanged( object sender,EventArgs e )
{
//处理_myBox的TextChanged事件
}
}
public event EventHandler Click;在需要激活事件的地方:
if(Click != null)
{
Click(this, EventArgs.Empty); // 或者是你从EventArgs类继承的类
}