功能定义：路由事件是一种可以针对元素树中的多个侦听器（而不是仅针对引发该事件的对象）调用处理程序的事件。
实现定义：路由事件是一个 CLR 事件，可以由RouteEvent 类的实例提供支持并由 Windows Presentation Foundation (WPF) 事件系统来处理。
实例：
Xaml
<Border Height="" Width="" BorderBrush="Gray" BorderThickness="">
<StackPanel Background="LightGray" Orientation="Horizontal" Button.Click="CommonClickHandler">
<Button Name="YesButton" Width="Auto" >Yes</Button>
<Button Name="NoButton" Width="Auto" >No</Button>
<Button Name="CancelButton" Width="Auto" >Cancel</Button>
</StackPanel>
</Border>
在这个简化的元素树中，Click事件的源是某个 Button元素，而所单击的 Button是有机会处理该事件的第一个元素。 但是，如果附加到 Button的任何处理程序均未作用于该事件，则该事件将向上冒泡到元素树中的 Button父级（即 StackPanel）。 该事件可能会冒泡到 Border，然后会到达元素树的页面根（未显示出来）。
换言之，此Click事件的事件路由为：Button-->StackPanel-->Border-->...
路由事件的策略
Bubbling：路由事件随后会路由到后续的父元素，直到到达元素树的根。
Direct：只有源元素本身才有机会调用处理程序以进行响应
Tunneling：最初将在元素树的根处调用事件处理程序。
路由事件策略会因为一下因素改变：
事件处理函数
public delegate void RoutedEventHandler(Object Sender, RoutedEventArgs e);
public delegate void MouseEventHandler(Object Sender, MouseEventArgs e);
RoutedEventArgs和MouseEventArgs包含路由事件的信息
如果设置"Handled"属性为True，路由事件会停止传递
类和实例事件处理函数
事件处理函数有两种类型，前一种是普通事件处理函数，"实例事件处理函数"，另一种是通过EventManager.RegisterClassHandler方法将一个事件处理函数和类关联起来，"类事件处理函数"，优先级更高
实例：(取自《葵花宝典--WPF自学手册》6.5)
自定义Button类
public class MySimpleButton : Button
{
static MySimpleButton()
{
EventManager.RegisterClassHandler(typeof(MySimpleButton), CustomClickEvent, new RoutedEventHandler(CustomClickClassHandler), false);
} public event EventHandler ClassHandlerProcessed;
public static void CustomClickClassHandler(Object sender, RoutedEventArgs e)
{
MySimpleButton simpBtn = sender as MySimpleButton;
EventArgs args = new EventArgs();
simpBtn.ClassHandlerProcessed(simpBtn, e);
} //Create and register routed event, routing strategies: Bubble
public static readonly RoutedEvent CustomClickEvent = EventManager.RegisterRoutedEvent(
"CustomClick",
RoutingStrategy.Bubble,
typeof(RoutedEventHandler),
typeof(MySimpleButton)); //CLR event wrapper
public event RoutedEventHandler CustomClick
{
add { AddHandler(CustomClickEvent, value); }
remove { RemoveHandler(CustomClickEvent, value); }
} //Raise CustomClickEvent
void RaiseCustomClickEvent()
{
RoutedEventArgs newEventArgs = new RoutedEventArgs(MySimpleButton.CustomClickEvent);
RaiseEvent(newEventArgs);
} //Onclick
protected override void OnClick()
{
RaiseCustomClickEvent();
} }
MainWindow.xaml
<Window x:Class="Alex_WPFAPPDemo02.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:custom="clr-namespace:Alex_WPFAPPDemo02"
custom:MySimpleButton.CustomClick="InsertList"
Title="MainWindow" Height="" Width="">
<Grid Margin="" custom:MySimpleButton.CustomClick="InsertList" Name="Grid1">
<Grid.RowDefinitions>
<RowDefinition Height="Auto" />
<RowDefinition Height="*" />
<RowDefinition Height="Auto" />
<RowDefinition Height="Auto" />
</Grid.RowDefinitions>
<custom:MySimpleButton x:Name="simpBtn" CustomClick="InsertList">
My Simple Button
</custom:MySimpleButton>
<ListBox Margin="" Name="listBox" Grid.Row="" />
<CheckBox Margin="" Grid.Row="" Name="chkHandle">
Handle first event
</CheckBox>
<Button Grid.Row="" HorizontalAlignment="Right" Margin="" Padding="" Click="clear">
Clear List
</Button>
</Grid>
</Window>
MainWindow.xaml.cs
protected int eventCounter = ;
private void InsertList(object sender, RoutedEventArgs e)
{
eventCounter++;
string message = "#" + eventCounter.ToString() + ":\r\n"
+ "InsertList\r\n"
+ " Sender: " + sender.ToString() + "\r\n"
+ " Source: " + e.Source + "\r\n"
+ "Original Source: " + e.OriginalSource;
listBox.Items.Add(message);
e.Handled = (bool)chkHandle.IsChecked;
} private void clear(object sender, RoutedEventArgs e)
{
eventCounter = ;
listBox.Items.Clear();
}
添加类处理函数
static MySimpleButton()
{
EventManager.RegisterClassHandler(typeof(MySimpleButton), CustomClickEvent, new RoutedEventHandler(CustomClickClassHandler), false);
} public event EventHandler ClassHandlerProcessed;
public static void CustomClickClassHandler(Object sender, RoutedEventArgs e)
{
MySimpleButton simpBtn = sender as MySimpleButton;
EventArgs args = new EventArgs();
simpBtn.ClassHandlerProcessed(simpBtn, e);
}
完善代码
public MainWindow()
{
InitializeComponent();
this.simpBtn.ClassHandlerProcessed += new EventHandler(ButtonRaisedClass);
}private void ButtonRaisedClass(object sender, EventArgs e)
{
eventCounter++;
string message = "#" + eventCounter.ToString() + ":\r\n"
+ "Windows Class Handler\r\n"
+ " Sender: " + sender.ToString();
listBox.Items.Add(message);
} private void ProcessHanldersToo(Object sender, RoutedEventArgs e)
{
eventCounter++;
string message = "#" + eventCounter.ToString() + ":\r\n"
+ "ProcessHanldersToo\r\n"
+ " Sender: " + sender.ToString()
+ " Source: " + e.Source + "\r\n"
+ "Original Source: " + e.OriginalSource;
listBox.Items.Add(message);
} private void Window_Loaded(object sender, RoutedEventArgs e)
{
Grid1.AddHandler(MySimpleButton.CustomClickEvent, new RoutedEventHandler(ProcessHanldersToo), true);
}
可以查看路由事件的线路
To be continue...