WPF UserControl 上下文菜单可见性绑定 [英] WPF UserControl Context Menu Visibility Binding

问题描述

我的用户控件上下文菜单可见性无法绑定依赖属性.有什么想法吗?

My user control context menu visibility can't bind a dependency property. Any idea?

这是我的 WPF 代码

Here is my WPF code

<UserControl.ContextMenu>
    <ContextMenu Visibility="{Binding ElementName=wellControl, Path=IsInCompactMode, Converter={StaticResource BooleanToVisibilityConverter}}">
    <MenuItem Command="local:GCommands.Edit" />
    <MenuItem Command="local:GCommands.Delete" />
    <MenuItem Command="local:GCommands.ExportFcsFiles" />
    <MenuItem Command="local:GCommands.BatchExportStatistics" />
    <Separator/>
    <MenuItem Command="local:GCommands.SaveAs" Header="Save As..." />
    </ContextMenu>
</UserControl.ContextMenu>

如果我设置 Visibility="Hidden" 它将对我有用.像这样:

If I set Visibility="Hidden" it will work for me. like this:

<ContextMenu Visibility="Hidden"/>

如果用这个就不行了

<ContextMenu Visibility="{Binding ElementName=wellControl, Path=IsInCompactMode, Converter={StaticResource BooleanToVisibilityConverter}}">

我很确定 Visibility="{Binding ElementName=wellControl, Path=IsInCompactMode, Converter={StaticResource BooleanToVisibilityConverter}}" 没有问题，因为它适用于其他人.

I'm pretty sure Visibility="{Binding ElementName=wellControl, Path=IsInCompactMode, Converter={StaticResource BooleanToVisibilityConverter}}" has not problem, cuz it works for others.

这是我的依赖属性

public bool IsInCompactMode
        {
            get {return (bool)GetValue(IsInCompactModeProperty); }
            set {SetValue(IsInCompactModeProperty, value); }
        }
        public static readonly DependencyProperty IsInCompactModeProperty =
            DependencyProperty.Register("IsInCompactMode", typeof(bool), typeof(WellControl), new PropertyMetadata(false));

这个方法我试过了，好像还是不行，真是奇怪！！！

I tried this way, it seems it still doesn't work, this is really weird!!!

<ContextMenu x:Name="menu" IsOpen="{Binding ElementName=wellControl, Path=IsInCompactMode}"> 

我真的很困惑，怎么了?Binding ElementName=wellControl, Path=IsInCompactMode"适用于用户控件的其他部分，只是不适用于奇怪的上下文菜单?没有意义

I'm really confuse about it, what's wrong? "Binding ElementName=wellControl, Path=IsInCompactMode" works for other part of the user control, just doesn't work for the weird context menu? it doesn't make sence

推荐答案

1> ContextMenu、Popups、DataGridColumns 不是可视化树的一部分.所以使用 ElementName 或 RelativeSource 的绑定不会像那样工作.

1> ContextMenu, Popups, DataGridColumns are not part of visual tree. So the binding using ElementName or RelativeSource wont work just like that.

2> 如果您希望上下文菜单在特定情况下不显示，请使用触发器从视觉对象本身取消设置上下文菜单.

      <TextBlock Text="ContextMenu is not shown when DataContext.IsShow is false"}">
            <TextBlock.Style>
                <Style TargetType="{x:Type TextBlock}">
                    <Setter Property="ContextMenu"
                            Value="{StaticResource TextBlockContextMenu}" />
                   <Style.Triggers>
                       <DataTrigger Binding="{Binding IsShow}"
                                    Value="False">
                            <Setter Property="ContextMenu"
                                    Value="{x:Null}" />
                       </DataTrigger>   
                   </Style.Triggers>
                </Style>
            </TextBlock.Style>
      </TextBlock>

3> 要将这些项目附加到可视化树，以便绑定起作用，我们使用代理元素方法...

3> To attach these items to the visual tree, so that binding works, we use the proxy element method...

绑定数据网格列可见性MVVM

我更喜欢第二步.

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