如何在以编程方式打开上下文菜单时引发ContextMenuOpening事件

本文关键字：菜单 事件 ContextMenuOpening 上下文 编程 方式打 | 更新日期: 2023-09-27 18:07:00

当我用<control>.ContextMenu.IsOpen = true打开上下文菜单时，上下文菜单变得可见，但没有触发打开或关闭事件。

当我以编程方式打开上下文菜单时，我如何确保ContextMenuOpening和ContextMenuClosing事件被引发?

演示:

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>

和后面的代码

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");
}

右击按钮时的行为:

上下文菜单正在打开。

输出为:

Opening #1
Opening #2
Closing #1
Closing #2

左键点击按钮时的行为:

上下文菜单正在打开。

输出为:

<Nothing>

如何在以编程方式打开上下文菜单时引发ContextMenuOpening事件

问题是你已经在ContextMenuOpening of Button上附加了事件，并且由于你手动调用ContextMenu，事件没有触发

所以要获取事件，从ContextMenu

中附加打开和关闭事件
    public MainWindow() // Constructor
    {
        InitializeComponent();
        ContextMenuButton.ContextMenu.Opened += (sender, args) => Debug.Print("Opening #2");
        ContextMenuButton.ContextMenu.Closed += (sender, args) => Debug.Print("Closing #2");
    }

xaml 

    <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>

events, 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。

这应该能解决你的问题

open事件与open事件有区别。通常，打开事件用于在菜单显示之前动态构建菜单。以上解决方法在这种情况下不起作用。

`
 // 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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