ContextMenu上下文菜单必须要依附于一个“宿主控件”。由于FrameworkElement基类有一个叫ContextMenu的属性，代表了鼠标右键时弹出一个菜单，所以大多数控件都可以设置“上下文菜单”。

ContextMenu继承于MenuBase，而MenuBase继承于ItemsControl。所以，ContextMenu本质上也是一个集合控件。而它的元素则是MenuItem。在用法上，与Menu控件差不多。

一、ContextMenu的定义

public class ContextMenu : MenuBase
{
    public static readonly DependencyProperty HorizontalOffsetProperty;
    public static readonly RoutedEvent OpenedEvent;
    public static readonly DependencyProperty StaysOpenProperty;
    public static readonly DependencyProperty CustomPopupPlacementCallbackProperty;
    public static readonly DependencyProperty HasDropShadowProperty;
    public static readonly RoutedEvent ClosedEvent;
    public static readonly DependencyProperty PlacementRectangleProperty;
    public static readonly DependencyProperty PlacementTargetProperty;
    public static readonly DependencyProperty IsOpenProperty;
    public static readonly DependencyProperty VerticalOffsetProperty;
    public static readonly DependencyProperty PlacementProperty;

    public ContextMenu();

    public double HorizontalOffset { get; set; }
    public bool StaysOpen { get; set; }
    public CustomPopupPlacementCallback CustomPopupPlacementCallback { get; set; }
    public bool HasDropShadow { get; set; }
    public PlacementMode Placement { get; set; }
    public Rect PlacementRectangle { get; set; }
    public UIElement PlacementTarget { get; set; }
    public bool IsOpen { get; set; }
    public double VerticalOffset { get; set; }
    protected internal override bool HandlesScrolling { get; }

    public event RoutedEventHandler Closed;
    public event RoutedEventHandler Opened;

    protected virtual void OnClosed(RoutedEventArgs e);
    protected override AutomationPeer OnCreateAutomationPeer();
    protected override void OnIsKeyboardFocusWithinChanged(DependencyPropertyChangedEventArgs e);
    protected override void OnKeyDown(KeyEventArgs e);
    protected override void OnKeyUp(KeyEventArgs e);
    protected virtual void OnOpened(RoutedEventArgs e);
    protected override void PrepareContainerForItemOverride(DependencyObject element, object item);
    protected internal override void OnVisualParentChanged(DependencyObject oldParent);

}

二、属性成员

三、ContextMenu示例

<Grid>
    <Border Background="LightBlue" Width="200" Height="100" CornerRadius="15">
        <Border.ContextMenu>
            <ContextMenu>
                <MenuItem Header="复制"/>
                <MenuItem Header="粘贴"/>
                <MenuItem Header="删除"/>
                <MenuItem Header="关于"/>
            </ContextMenu>
        </Border.ContextMenu>
    </Border>        
</Grid>

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文件名：046-《ContextMenu上下文菜单》-源代码
链接：https://pan.baidu.com/s/1yu-q4tUtl0poLVgmcMfgBA
提取码：wpff

——重庆教主 2023年9月8日