Question

当我双击树项目时如何禁用树项目的折叠/展开？我仍然想通过单击切换按钮来做到这一点，但是当我双击项目时不希望这样做。

这是我拥有的XAML：

<TreeView Grid.Column="0" Grid.Row="0" ItemsSource="{Binding Categories}" helpers:TreeViewHelper.SelectedItem="{Binding SelectedCategory, Mode=TwoWay}" >
    <TreeView.ItemContainerStyle>
        <Style TargetType="{x:Type TreeViewItem}">
            <Setter Property="IsExpanded" Value="True"/>
        </Style>
    </TreeView.ItemContainerStyle>
    <TreeView.ItemTemplate>
        <HierarchicalDataTemplate DataType="{x:Type core:Category}" ItemsSource="{Binding SubCategories}">
            <Label Content="{Binding Name}">
                <i:Interaction.Triggers>
                    <i:EventTrigger EventName="MouseDoubleClick">
                        <i:InvokeCommandAction Command="{Binding RelativeSource={RelativeSource AncestorType=Window}, Path=DataContext.CreateGroupsFromCategoryCommand , Mode=OneWay}" CommandParameter="{Binding}" />
                    </i:EventTrigger>
                </i:Interaction.Triggers>
            </Label>
        </HierarchicalDataTemplate>
    </TreeView.ItemTemplate>
</TreeView>

我只想在XAML中这样做。

谢谢您的帮助。

Answer 1

您应在treeviewitem上取消双击事件：

<TreeView Grid.Column="0" Grid.Row="0" ItemsSource="{Binding Categories}" helpers:TreeViewHelper.SelectedItem="{Binding SelectedCategory, Mode=TwoWay}" TreeViewItem.PreviewMouseDoubleClick="TreeViewItem_PreviewMouseDoubleClick" >
    <TreeView.ItemContainerStyle>
        <Style TargetType="{x:Type TreeViewItem}">
            <Setter Property="IsExpanded" Value="True"/>
        </Style>
    </TreeView.ItemContainerStyle>
    <TreeView.ItemTemplate>
        <HierarchicalDataTemplate DataType="{x:Type core:Category}" ItemsSource="{Binding SubCategories}">
            <Label Content="{Binding Name}">
                <i:Interaction.Triggers>
                    <i:EventTrigger EventName="MouseDoubleClick">
                        <i:InvokeCommandAction Command="{Binding RelativeSource={RelativeSource AncestorType=Window}, Path=DataContext.CreateGroupsFromCategoryCommand , Mode=OneWay}" CommandParameter="{Binding}" />
                    </i:EventTrigger>
                </i:Interaction.Triggers>
            </Label>
        </HierarchicalDataTemplate>
    </TreeView.ItemTemplate>
</TreeView>

后面的代码：

private void TreeViewItem_PreviewMouseDoubleClick(object sender, MouseButtonEventArgs e)
{
    //this will suppress the event that is causing the nodes to expand/contract 
    e.Handled = true;
}

Answer 2

您可以在后面的视图代码中实现自定义EventTrigger，如此处建议的：https://stackoverflow.com/a/7688249/1206431

public class HandlingEventTrigger : System.Windows.Interactivity.EventTrigger
{
    protected override void OnEvent(System.EventArgs eventArgs)
    {
        var routedEventArgs = eventArgs as RoutedEventArgs;
        if (routedEventArgs != null)
            routedEventArgs.Handled = true;

        base.OnEvent(eventArgs);
    }
}

像这样xmlns:views="clr-namespace:YourNamespace.Views"

将名称空间添加到视图中

然后将<i:EventTrigger EventName="MouseDoubleClick">替换为<local:HandlingEventTrigger EventName="PreviewMouseDoubleClick">。

HandlingEventTrigger 将阻止事件沿视觉树进一步传递，因此不会展开/折叠树，而是使用 PreviewMouseDoubleClick 而不是 MouseDoubleClick < / strong>，您仍可以触发自己的命令。

如何在双击禁用WPF TreeView中的树项目的展开/折叠

2 个答案: