c# - 菜单项打开和关闭事件

Question

每当菜单项的子菜单打开时，我想处理一个事件。关闭也一样。我怎样才能做到这一点？

Answer 1

很容易。订阅 aMenuItem的SubmenuOpened事件。传统的做法：

MidItem.SubmenuOpened += new RoutedEventHandler(MidItem_SubmenuOpened);

private void MidItem_SubmenuOpened(object sender, RoutedEventArgs e)
{
    //Menu Open Logic Here
}

或者酷炫的动态方法：

MidItem.SubmenuOpened += delegate(object sender, RoutedEventArgs e)
{
    //Menu Open Logic Here
};

Answer 2

不确定您想要什么，但请查看这些事件ContextMenu和MenuItem：

ContextMenu：

http://msdn.microsoft.com/en-us/library/system.windows.controls.contextmenu_events.aspx

MenuItem：

http://msdn.microsoft.com/en-us/library/system.windows.controls.menuitem_events.aspx

我认为ContextMenuOpening并且ContextMenuClosing可能很有趣；）

Answer 3

如果您希望在真正开放之前打开，您可以将 menuitem 子类化

Imports System.ComponentModel
Public Class CustomMenuItem
    Inherits MenuItem

    Public Event SubMenuOpening(sender As Object, e As CancelEventArgs)
    Public Event SubMenuClosing(sender As Object, e As CancelEventArgs)
    Protected Overrides Sub OnPropertyChanged(e As DependencyPropertyChangedEventArgs)
        If e.Property Is MenuItem.IsSubmenuOpenProperty Then
            Dim MyCancelEventArgs As New CancelEventArgs
            If e.NewValue Then
                RaiseEvent SubMenuOpening(Me, MyCancelEventArgs)
                If MyCancelEventArgs.Cancel Then Me.IsSubmenuOpen = False
            Else
                RaiseEvent SubMenuClosing(Me, MyCancelEventArgs)
                If MyCancelEventArgs.Cancel Then Me.IsSubmenuOpen = True
            End If
        End If
        MyBase.OnPropertyChanged(e)
    End Sub

End Class

我知道这是 VB，但它很容易转换。另外，使用 CancelEventArgs，您可以模拟取消打开（或关闭）。