[英]How to raise ContextMenuOpening event when opening context menu programmatically
当我使用<control>.ContextMenu.IsOpen = true
打开上下文菜单时,上下文菜单变得可见,但不会触发打开或关闭事件。
当我以编程方式打开上下文菜单时,如何确保引发ContextMenuOpening
和ContextMenuClosing
事件?
看下面的XAML
<Button Name="ContextMenuButton"
Content="Click me!"
Click="ContextMenuButton_Click"
ContextMenuOpening="ContextMenuButton_OnContextMenuOpening"
ContextMenuClosing="ContextMenuButton_OnContextMenuClosing">
<Button.ContextMenu>
<ContextMenu>
<MenuItem Header="First element" />
<MenuItem Header="Second element" />
</ContextMenu>
</Button.ContextMenu>
</Button>
以及以下代码隐藏
public MainWindow() // Constructor
{
InitializeComponent();
ContextMenuButton.ContextMenuOpening += (sender, args) => Debug.Print("Opening #2");
ContextMenuButton.ContextMenuClosing += (sender, args) => Debug.Print("Closing #2");
}
private void ContextMenuButton_Click(object sender, RoutedEventArgs e)
{
Button button = (sender as Button);
button.ContextMenu.IsOpen = true; // How should I open the ContextMenu?
}
private void ContextMenuButton_OnContextMenuOpening(object sender, ContextMenuEventArgs e)
{
Debug.Print("Opening #1");
}
private void ContextMenuButton_OnContextMenuClosing(object sender, ContextMenuEventArgs e)
{
Debug.Print("Closing #1");
}
上下文菜单正在打开。
输出是:
Opening #1
Opening #2
Closing #1
Closing #2
上下文菜单正在打开。
输出是:
<Nothing>
问题是您在 Button 的 ContextMenuOpening 上附加了事件,并且由于您手动调用了 ContextMenu,因此事件没有触发
所以为了让事件附加来自 ContextMenu 的 Opened 和 Closed 事件
public MainWindow() // Constructor
{
InitializeComponent();
ContextMenuButton.ContextMenu.Opened += (sender, args) => Debug.Print("Opening #2");
ContextMenuButton.ContextMenu.Closed += (sender, args) => Debug.Print("Closing #2");
}
xml
<Button Name="ContextMenuButton"
Content="Click me!"
Click="ContextMenuButton_Click" >
<Button.ContextMenu>
<ContextMenu Opened="ContextMenuButton_OnContextMenuOpening" Closed="ContextMenuButton_OnContextMenuClosing">
<MenuItem Header="First element" />
<MenuItem Header="Second element" />
</ContextMenu>
</Button.ContextMenu>
</Button>
事件,ContextMenuEventArgs 更改为 RoutedEventArgs
private void ContextMenuButton_OnContextMenuOpening(object sender, RoutedEventArgs e)
{
Debug.Print("Opening #1");
}
private void ContextMenuButton_OnContextMenuClosing(object sender, RoutedEventArgs e)
{
Debug.Print("Closing #1");
}
按钮点击保持不变。
这应该可以解决您的问题
Opened 和 Opening 事件之间存在差异。 通常 Opening 事件用于在菜单显示之前动态构建菜单。 在这种情况下,上述解决方案将不起作用。
`
// Raise Context menu Opening Event
var args = CreateInstance<ContextMenuEventArgs>(element, true);
args.RoutedEvent = FrameworkElement.ContextMenuOpeningEvent;
element.RaiseEvent(args);
contextMenu.IsOpen = true;
`
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