Control.PreviewMouseDoubleClick 事件

定义

在用户单击鼠标按钮两次或更多次时发生。Occurs when a user clicks the mouse button two or more times.

public:
 event System::Windows::Input::MouseButtonEventHandler ^ PreviewMouseDoubleClick;
public event System.Windows.Input.MouseButtonEventHandler PreviewMouseDoubleClick;
member this.PreviewMouseDoubleClick : System.Windows.Input.MouseButtonEventHandler 
Public Custom Event PreviewMouseDoubleClick As MouseButtonEventHandler 

示例

下面的示例演示如何将事件处理程序PreviewMouseDoubleClick附加到事件。The following example shows how to attach an event handler the PreviewMouseDoubleClick event.

<Button Name="btn1" Foreground="Black" 
        PreviewMouseDoubleClick="ChangeForeground">
  Foreground
</Button>

下面的示例演示PreviewMouseDoubleClick事件的事件处理程序。The following example shows the event handler of the PreviewMouseDoubleClick event.

void ChangeForeground(object sender, RoutedEventArgs e)
{
    if (btn1.Foreground == Brushes.Green)
    {
        btn1.Foreground = Brushes.Black;
        btn1.Content = "Foreground";
    }
    else
    {
        btn1.Foreground = Brushes.Green;
        btn1.Content = "Control foreground(text) changes from black to green.";
    }
}
Private Sub ChangeForeground(ByVal Sender As Object, ByVal e As System.Windows.Input.MouseButtonEventArgs)

    If (btn1.Foreground Is Brushes.Green) Then
        btn1.Foreground = Brushes.Black
        btn1.Content = "Foreground"
    Else
        btn1.Foreground = Brushes.Green
        btn1.Content = "Control foreground(text) changes from black to green."
    End If

End Sub

注解

尽管此路由事件似乎是通过元素树跟踪隧道路由, 但实际上它是一个直接路由事件, 每个UIElement事件都由元素树逐个引发。Although this routed event seems to follow a tunneling route through an element tree, it actually is a direct routed event that is raised along the element tree by each UIElement. 如果在PreviewMouseDoubleClick事件处理Handled程序中true将属性设置为, 则PreviewMouseDoubleClick在将Handled设置为false的情况下将发生MouseDoubleClick沿路由的后续事件, 但会发生Handled事件设置为trueIf you set the Handled property to true in a PreviewMouseDoubleClick event handler, subsequent PreviewMouseDoubleClick events along the route will occur with Handled set to false, but the MouseDoubleClick event will occur with Handled set to true. 这是控件使用者的高级事件, 当用户双击控件并处理应用程序中的事件时, 这些用户希望获得通知。This is a higher-level event for control consumers who want to be notified when the user double-clicks the control and to handle the event in an application.

当等于2时PreviewMouseLeftButtonDown ClickCount , 要处理鼠标双击的控件作者应使用该事件。Control authors who want to handle mouse double clicks should use the PreviewMouseLeftButtonDown event when ClickCount is equal to two. 这将导致的状态Handled在元素树中的另一个元素处理事件时适当地传播。This will cause the state of Handled to propagate appropriately in the case where another element in the element tree handles the event.

Control类定义和MouseDoubleClick事件, 而不是对应的单击事件。 PreviewMouseDoubleClickThe Control class defines the PreviewMouseDoubleClick and MouseDoubleClick events, but not corresponding single-click events. 若要查看用户是否已单击控件一次, 请处理MouseDown事件 (或其对应的事件之一), 并检查ClickCount属性值是否为1。To see if the user has clicked the control once, handle the MouseDown event (or one of its counterparts) and check whether the ClickCount property value is 1.

路由事件信息Routed Event Information

标识符字段Identifier field PreviewMouseDoubleClickEvent
路由策略Routing strategy 直接Direct
委托Delegate MouseButtonEventHandler

适用于