仅针对ListViewItem的上下文菜单

Question

我有一个上下文菜单 - 问题是我需要它只在单击列表视图项时才打开。现在，如果我单击列表视图或标题中的任何位置，它都会打开。

<ListView> 
    <ListView.ContextMenu>
        <ContextMenu>
            <MenuItem Header="More Info" Command="{Binding MoreInfo}" />
        </ContextMenu>
     </ListView.ContextMenu>
     <ListView.View> 
         <GridView> 
           <!-- columns and stuff here -->
         </GridView>
     </ListView.View>
 </ListView>

我尝试将ContextMenu作为资源添加并应用为样式，但这会破坏命令（点击"更多信息"应该打开对话框窗口，但这种方式不起作用）

<ListView.Resources>
    <ContextMenu x:Key="ItemContextMenu">
        <MenuItem Header="More Info" Command="{Binding MoreInfo}" Background="WhiteSmoke" />
    </ContextMenu>
</ListView.Resources>
<ListView.ItemContainerStyle>
    <Style TargetType="{x:Type ListViewItem}" >
        <Setter Property="ContextMenu" Value="{StaticResource ItemContextMenu}" />
    </Style>
</ListView.ItemContainerStyle>

我不确定该如何将上下文菜单限制在仅列表项中并使命令生效。

- ctd25

Answer 1

在模板中使用RelativeSource绑定命令，它就会起作用：

<ListView.Resources>
    <ContextMenu x:Key="ItemContextMenu">
        <MenuItem Header="More Info" Command="{Binding Path=DataContext.MoreInfo, RelativeSource={RelativeSource Mode=FindAncestor, AncestorType=ListView}}" Background="WhiteSmoke" />
    </ContextMenu>
</ListView.Resources>

<ListView.ItemContainerStyle>
    <Style TargetType="{x:Type ListViewItem}" >
        <Setter Property="ContextMenu" Value="{StaticResource ItemContextMenu}" />
    </Style>
</ListView.ItemContainerStyle>

- Vyacheslav Volkov

---

谢谢，这个可行。你能否解释一下这是在做什么？我对FindAncestor的作用有点模糊。 - ctd25

在您的情况下，RelativeSource 试图在 UI 树中查找第一个 ListView 控件并将其用作绑定源。因此，我们必须先写 DataContext，然后是属性名称。 - Vyacheslav Volkov

Answer 2

在这篇非常有帮助的文章上进行扩展...如果您的ContextMenu具有自定义按钮或其他对象，位于ControlTemplate中，我已将上面的答案与Closing ContextMenu with Templated MenuItems的答案结合起来，以便当用户单击Button时，ContextMenu正常关闭，仅使用XAML。这花费了大约10个小时的时间来完成。希望它能为您节省时间。支持MVVM ICommand用法。我还使用了[此文章][2]中的ContextMenu的Style来消除90年代的外观。

<ListView.Resources>
    <ContextMenu x:Key="ItemContextMenu" Style="{StaticResource HorizontalContextMenu}">
        <MenuItem>
            <MenuItem.Template>
                <ControlTemplate>
                    <Grid MinHeight="50" MinWidth="50">
                        <Button Style="{StaticResource CloseAppButton}" Command="{Binding Path=DataContext.DeleteCommand, RelativeSource={RelativeSource Mode=FindAncestor, AncestorType=ListView}}" >
                            <Button.Triggers>
                                <EventTrigger RoutedEvent="Button.Click">
                                    <BeginStoryboard>
                                        <Storyboard>
                                            <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="(ContextMenu.IsOpen)" Storyboard.Target="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType=ContextMenu}}">
                                                <DiscreteObjectKeyFrame KeyTime="0:0:0">
                                                    <DiscreteObjectKeyFrame.Value>
                                                        <sys:Boolean>False</sys:Boolean>
                                                    </DiscreteObjectKeyFrame.Value>
                                                </DiscreteObjectKeyFrame>
                                            </ObjectAnimationUsingKeyFrames>
                                        </Storyboard>
                                    </BeginStoryboard>
                                </EventTrigger>
                            </Button.Triggers>
                        </Button>
                    </Grid>
                </ControlTemplate>
            </MenuItem.Template>
        </MenuItem>

        <MenuItem>
            <MenuItem.Template>
                <ControlTemplate>
                    <Grid MinHeight="50" MinWidth="50">
                        <Button Style="{StaticResource AddButton}" Command="{Binding Path=DataContext.TestCommand, RelativeSource={RelativeSource Mode=FindAncestor, AncestorType=ListView}}" >
                            <Button.Triggers>
                                <EventTrigger RoutedEvent="Button.Click">
                                    <BeginStoryboard>
                                        <Storyboard>
                                            <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="(ContextMenu.IsOpen)" Storyboard.Target="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType=ContextMenu}}">
                                                <DiscreteObjectKeyFrame KeyTime="0:0:0">
                                                    <DiscreteObjectKeyFrame.Value>
                                                        <sys:Boolean>False</sys:Boolean>
                                                    </DiscreteObjectKeyFrame.Value>
                                                </DiscreteObjectKeyFrame>
                                            </ObjectAnimationUsingKeyFrames>
                                        </Storyboard>
                                    </BeginStoryboard>
                                </EventTrigger>
                            </Button.Triggers>
                        </Button>
                    </Grid>
                </ControlTemplate>
            </MenuItem.Template>
        </MenuItem>

        <MenuItem>
            <MenuItem.Template>
                <ControlTemplate>
                    <Grid MinHeight="50" MinWidth="50">
                        <Button Style="{StaticResource PluginInfoButton}" Command="{Binding Path=DataContext.TestCommand, RelativeSource={RelativeSource Mode=FindAncestor, AncestorType=ListView}}" >
                            <Button.Triggers>
                                <EventTrigger RoutedEvent="Button.Click">
                                    <BeginStoryboard>
                                        <Storyboard>
                                            <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="(ContextMenu.IsOpen)" Storyboard.Target="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType=ContextMenu}}">
                                                <DiscreteObjectKeyFrame KeyTime="0:0:0">
                                                    <DiscreteObjectKeyFrame.Value>
                                                        <sys:Boolean>False</sys:Boolean>
                                                    </DiscreteObjectKeyFrame.Value>
                                                </DiscreteObjectKeyFrame>
                                            </ObjectAnimationUsingKeyFrames>
                                        </Storyboard>
                                    </BeginStoryboard>
                                </EventTrigger>
                            </Button.Triggers>
                        </Button>
                    </Grid>
                </ControlTemplate>
            </MenuItem.Template>
        </MenuItem>
    </ContextMenu>

</ListView.Resources>
<ListView.ItemContainerStyle>
    <Style TargetType="{x:Type ListViewItem}" >
        <Setter Property="ContextMenu" Value="{StaticResource ItemContextMenu}" />
        <Setter Property="HorizontalContentAlignment" Value="Stretch"/>
    </Style>
</ListView.ItemContainerStyle>

- Slip