如何将命令绑定到项目上 TreeView 内的上下文菜单中？

Question

我希望能够通过单击上下文菜单中的命令对 TreeView 中的项目执行命令。更具体地说，只有当项目是某种类型时（xxTreeViewItem 是一个具有 2 个子类型的接口）。

   <Grid Name="Root" commonExtensions:EnterKeyUpdateExtension.IsEnabled="True">

    <StackPanel Orientation="Vertical" Grid.Row="0">
        <Button Content="Center on" Command="{Binding Path=CenterOnCommand}" Margin="5,10,5,0"/>
    </StackPanel>
        <Grid>
            <TreeView Grid.Row="0" Name="xxTreeView" DataContext="{Binding Path=xxViewModel}" ItemsSource="{Binding Path=Items}">
                <TreeView.ItemContainerStyle>
                    <Style TargetType="{x:Type TreeViewItem}">
                        <Setter Property="ContextMenu">
                            <Setter.Value>
                                <ContextMenu>
                                    <MenuItem Header="Center On" Command="{Binding CenterOnCommand}"/>
                                </ContextMenu>
                            </Setter.Value>
                        </Setter>
                    </Style>
                </TreeView.ItemContainerStyle>
                <TreeView.ItemTemplate>
                    <HierarchicalDataTemplate ItemsSource="{Binding Path=Items}" DataType="{x:Type localViewItems:xxTreeViewItem}">
                        <TextBlock Text="{Binding Name}" VerticalAlignment="Center"/>
                    </HierarchicalDataTemplate>
                </TreeView.ItemTemplate>
            </TreeView>

顶部按钮中的命令有效，但在上下文菜单中无效。我尝试了几种绑定并找到了祖先，但 none 它有效。有XAML唯一的解决方案吗？

Answer 1

ContextMenu不属于可视树，所以不继承你的TreeView的DataContext。因此，您需要使用 PlacementTarget 属性:

将其传递给您的 ContextMenu

<TreeView.ItemContainerStyle>
    <Style TargetType="{x:Type TreeViewItem}">
        <Setter Property="Tag" Value="{Binding RelativeSource={RelativeSource AncestorType=TreeView}, Path=DataContext}"></Setter>
        <Setter Property="ContextMenu">
            <Setter.Value>
                <ContextMenu DataContext="{Binding Path=PlacementTarget.Tag, RelativeSource={RelativeSource Self}}">
                    <MenuItem Header="Center On" Command="{Binding CenterOnCommand}" />
                </ContextMenu>
            </Setter.Value>
        </Setter>
    </Style>
</TreeView.ItemContainerStyle>

希望对您有所帮助

如何将命令绑定到项目上 TreeView 内的上下文菜单中？

How to bind command into a context menu that is inside TreeView on it's items?

c#

wpf

treeview

binding

command