通过

如何：创建自定义路由事件

  • 项目

若要使你的自定义事件支持事件路由，需要使用 RegisterRoutedEvent 方法注册 RoutedEvent。 此示例演示创建自定义路由事件的基础知识。

例

如以下示例所示，首先使用 RegisterRoutedEvent 方法注册 RoutedEvent。 按照约定，RoutedEvent 静态字段名称应以后缀 事件结尾。 在此示例中，事件的名称 Tap，事件路由策略 Bubble。 在注册调用之后，可以为事件提供添加和移除公共语言运行时 (CLR) 事件访问器。

请注意，即使事件是通过此特定示例中 OnTap 虚拟方法引发的，你如何引发事件或事件响应更改的方式取决于你的需求。

另请注意，此示例基本上实现了 Button的整个子类;该子类生成为单独的程序集，然后在单独的 XAML 页面上实例化为自定义类。 这是为了说明子类化控件可以插入到由其他控件组成的树中的概念，在这种情况下，这些控件上的自定义事件具有与任何本机 WPF 元素相同的事件路由功能。

public class MyButtonSimple: Button
{
    // Create a custom routed event by first registering a RoutedEventID
    // This event uses the bubbling routing strategy
    public static readonly RoutedEvent TapEvent = EventManager.RegisterRoutedEvent(
        "Tap", RoutingStrategy.Bubble, typeof(RoutedEventHandler), typeof(MyButtonSimple));

    // Provide CLR accessors for the event
    public event RoutedEventHandler Tap
    {
            add { AddHandler(TapEvent, value); }
            remove { RemoveHandler(TapEvent, value); }
    }

    // This method raises the Tap event
    void RaiseTapEvent()
    {
            RoutedEventArgs newEventArgs = new RoutedEventArgs(MyButtonSimple.TapEvent);
            RaiseEvent(newEventArgs);
    }
    // For demonstration purposes we raise the event when the MyButtonSimple is clicked
    protected override void OnClick()
    {
        RaiseTapEvent();
    }
}

Public Class MyButtonSimple
    Inherits Button

    ' Create a custom routed event by first registering a RoutedEventID
    ' This event uses the bubbling routing strategy
    Public Shared ReadOnly TapEvent As RoutedEvent = EventManager.RegisterRoutedEvent("Tap", RoutingStrategy.Bubble, GetType(RoutedEventHandler), GetType(MyButtonSimple))

    ' Provide CLR accessors for the event
    Public Custom Event Tap As RoutedEventHandler
        AddHandler(ByVal value As RoutedEventHandler)
            Me.AddHandler(TapEvent, value)
        End AddHandler

        RemoveHandler(ByVal value As RoutedEventHandler)
            Me.RemoveHandler(TapEvent, value)
        End RemoveHandler

        RaiseEvent(ByVal sender As Object, ByVal e As RoutedEventArgs)
            Me.RaiseEvent(e)
        End RaiseEvent
    End Event

    ' This method raises the Tap event
    Private Sub RaiseTapEvent()
        Dim newEventArgs As New RoutedEventArgs(MyButtonSimple.TapEvent)
        MyBase.RaiseEvent(newEventArgs)
    End Sub

    ' For demonstration purposes we raise the event when the MyButtonSimple is clicked
    Protected Overrides Sub OnClick()
        Me.RaiseTapEvent()
    End Sub

End Class

<Window  
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:custom="clr-namespace:SDKSample;assembly=SDKSampleLibrary"
    x:Class="SDKSample.RoutedEventCustomApp"

    >
    <Window.Resources>
      <Style TargetType="{x:Type custom:MyButtonSimple}">
        <Setter Property="Height" Value="20"/>
        <Setter Property="Width" Value="250"/>
        <Setter Property="HorizontalAlignment" Value="Left"/>
        <Setter Property="Background" Value="#808080"/>
      </Style>
    </Window.Resources>
    <StackPanel Background="LightGray">
        <custom:MyButtonSimple Name="mybtnsimple" Tap="TapHandler">Click to see Tap custom event work</custom:MyButtonSimple>
    </StackPanel>
</Window>

隧道事件以相同的方式创建，但在注册函数调用中将 RoutingStrategy 设置为 Tunnel。 按照约定，WPF 中的隧道事件以“预览”一词作为前缀。

若要查看浮泡事件的工作原理示例，请参阅 处理路由事件。

另请参阅