wpf - MVVM TreeView 单击节点

Question

我正在使用一个现有的 MVVM 项目，直到现在我都做得很好。我有一个 treeView 代码，我想要
按下时释放节点。换句话说，今天如果我单击任何节点，它就不再可选择(直到您单击另一个节点)。我希望能够多次单击同一节点。如果我双击 node ，我有“IsExpended”属性，它会转到这个代码部分。我看不到双击绑定(bind)，单击绑定(bind)在哪里...

这是xml

<UserControl x:Class="Envitech.Setup.Presentation.Views.TreeViewViews.StationTree" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:behaviour="clr-namespace:Envitech.Setup.Presentation.Extensions;assembly=Envitech.Setup.Presentation" xmlns:nodes="clr-namespace:Envitech.Setup.Presentation.ViewModels.TreeViewViewModels.Nodes" mc:Ignorable="d" xmlns:d="http://schemas.microsoft.com/expression/blend/2008" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" d:DesignHeight="226" d:DesignWidth="227" xmlns:ml="clr-namespace:Envitech.Setup.Presentation.ml_resources">
    <TreeView Margin="10 0 10 20" ItemsSource="{Binding Path=Root.Children}" VirtualizingStackPanel.IsVirtualizing="True" VirtualizingStackPanel.VirtualizationMode="Recycling">


    <TreeView.ItemContainerStyle>
        <Style TargetType="{x:Type TreeViewItem}">
            <Setter Property="IsSelected" Value="{Binding Path=IsSelected, Mode=TwoWay}"/>
            <Setter Property="IsExpanded" Value="{Binding Path=IsExpanded, Mode=TwoWay}" />
        </Style>
    </TreeView.ItemContainerStyle>
    <TreeView.Resources>
        <Style TargetType="{x:Type TreeViewItem}">
            <Setter Property="Background" Value="Transparent" />
            <Setter Property="HorizontalContentAlignment" Value="{Binding Path=HorizontalContentAlignment, RelativeSource={RelativeSource AncestorType={x:Type ItemsControl}}}" />
            <Setter Property="VerticalContentAlignment" Value="{Binding Path=VerticalContentAlignment, RelativeSource={RelativeSource AncestorType={x:Type ItemsControl}}}" />
            <Setter Property="Padding" Value="1,0,0,0" />
            <Setter Property="IsExpanded" Value="{Binding IsExpanded, Mode=TwoWay}" />
            <Setter Property="IsSelected" Value="{Binding IsSelected, Mode=TwoWay}" />
            <Setter Property="behaviour:TreeViewItemBehavior.IsBroughtIntoViewWhenSelected" Value="True" />
            <Setter Property="Template">
                <Setter.Value>
                    <ControlTemplate TargetType="{x:Type TreeViewItem}">
                        <Grid>
                            <Grid.ColumnDefinitions>
                                <ColumnDefinition MinWidth="19" Width="Auto" />
                                <ColumnDefinition Width="Auto" />
                                <ColumnDefinition Width="*" />
                            </Grid.ColumnDefinitions>
                            <Grid.RowDefinitions>
                                <RowDefinition Height="Auto" />
                                <RowDefinition />
                            </Grid.RowDefinitions>
                            <ToggleButton x:Name="Expander" IsChecked="{Binding Path=IsExpanded, RelativeSource={RelativeSource TemplatedParent}}" ClickMode="Press" />
                            <Border Grid.Column="1" x:Name="Selection_Border" Background="{TemplateBinding Background}" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Padding="{TemplateBinding Padding}">
                                <ContentPresenter HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" x:Name="PART_Header" ContentSource="Header" />
                            </Border>
                            <ItemsPresenter Grid.Column="1" Grid.ColumnSpan="2" Grid.Row="1" x:Name="ItemsHost" />
                        </Grid>
                        <ControlTemplate.Triggers>
                            <Trigger Property="IsExpanded" Value="false">
                                <Setter Property="Visibility" Value="Collapsed" TargetName="ItemsHost" />
                            </Trigger>
                            <Trigger Property="HasItems" Value="false">
                                <Setter Property="Visibility" Value="Hidden" TargetName="Expander" />
                            </Trigger>
                            <Trigger Property="IsSelected" Value="true">
                                <Setter Property="Background" Value="{DynamicResource {x:Static SystemColors.HighlightBrushKey}}" TargetName="Selection_Border" />
                                <Setter Property="Foreground" Value="{DynamicResource {x:Static SystemColors.HighlightTextBrushKey}}" />
                            </Trigger>
                            <MultiTrigger>
                                <MultiTrigger.Conditions>
                                    <Condition Property="IsSelected" Value="true" />
                                    <Condition Property="IsSelectionActive" Value="false" />
                                </MultiTrigger.Conditions>
                                <Setter Property="Background" Value="{DynamicResource {x:Static SystemColors.HighlightBrushKey}}" TargetName="Selection_Border" />
                                <Setter Property="Foreground" Value="{DynamicResource {x:Static SystemColors.HighlightTextBrushKey}}" />
                            </MultiTrigger>
                            <Trigger Property="IsEnabled" Value="false">
                                <Setter Property="Foreground" Value="{DynamicResource {x:Static SystemColors.GrayTextBrushKey}}" />
                            </Trigger>
                        </ControlTemplate.Triggers>
                    </ControlTemplate>
                </Setter.Value>
            </Setter>
        </Style>
        <!-- Style for the ToggleButton control used to expand/collapse a TreeViewItem control -->
        <Style TargetType="{x:Type ToggleButton}">
            <Setter Property="Focusable" Value="False" />
            <Setter Property="Width" Value="19" />
            <Setter Property="Height" Value="13" />
            <Setter Property="Template">
                <Setter.Value>
                    <ControlTemplate TargetType="{x:Type ToggleButton}">
                        <Border Width="19" Height="13" Background="#00FFFFFF" x:Name="Border">
                            <Border Width="9" Height="9" x:Name="Border1" SnapsToDevicePixels="True" BorderBrush="#FF9495A2" BorderThickness="1,1,1,1" CornerRadius="1,1,1,1">
                                <Border.Background>
                                    <LinearGradientBrush StartPoint="0,0" EndPoint="1,1">
                                        <GradientStop Color="#FFFFFFFF" Offset="0.4" />
                                        <GradientStop Color="#FFC6CEDA" Offset="1" />
                                    </LinearGradientBrush>
                                </Border.Background>
                                <Path Fill="#FF000000" Margin="1,1,1,1" x:Name="ExpandPath" Data="M0,2L0,3 2,3 2,5 3,5 3,3 5,3 5,2 3,2 3,0 2,0 2,2z" />
                            </Border>
                        </Border>
                        <ControlTemplate.Triggers>
                            <Trigger Property="IsChecked" Value="True">
                                <Setter Property="Data" Value="M0,2L0,3 5,3 5,2z" TargetName="ExpandPath" />
                            </Trigger>
                        </ControlTemplate.Triggers>
                    </ControlTemplate>
                </Setter.Value>
            </Setter>
        </Style>
        <DataTemplate DataType="{x:Type nodes:MonitorNode}">
            <StackPanel Orientation="Horizontal" Margin="0 2 0 0">
                <Image Source="{Binding ImageSource}" Width="16" Height="16" Margin="0 0 3 0" />
                <TextBlock Text="{x:Static ml:MultiLang._157}" x:Name="ML_0048" />
                <TextBlock Text="{Binding ID}" />
                <TextBlock Text="{x:Static ml:MultiLang._158}" x:Name="ML_0050" />
                <TextBlock Text="{Binding Name}" />
            </StackPanel>
        </DataTemplate>
        <HierarchicalDataTemplate DataType="{x:Type nodes:StationNode}" ItemsSource="{Binding Children}">
            <StackPanel Orientation="Horizontal" Margin="0 2 0 0">
                <StackPanel.ContextMenu>
                    <ContextMenu HasDropShadow="True">
                        <MenuItem Header="{x:Static ml:MultiLang._160}" Command="{Binding CopyMonitorsCommand}" x:Name="ML_0055" />
                        <MenuItem Header="{x:Static ml:MultiLang._159}" Command="{Binding PasteMonitorsCommand}" x:Name="ML_0056" />
                        <MenuItem Header="{x:Static ml:MultiLang._162}" Command="{Binding CopyStationsCommand}" x:Name="ML_0057" />
                        <MenuItem Header="{x:Static ml:MultiLang._161}" Command="{Binding PasteStationsCommand}" x:Name="ML_0058" />
                    </ContextMenu>
                </StackPanel.ContextMenu>
                <Image Source="{Binding ImageSource}" Width="16" Height="16" Margin="0 0 3 0" />
                <TextBlock Text="{x:Static ml:MultiLang._157}" x:Name="ML_0060" />
                <TextBlock Text="{Binding ID}" />
                <TextBlock Text="{x:Static ml:MultiLang._158}" x:Name="ML_0062" />
                <TextBlock Text="{Binding Name}" />
            </StackPanel>
        </HierarchicalDataTemplate>
        <HierarchicalDataTemplate DataType="{x:Type nodes:FilteringNode}" ItemsSource="{Binding Children}">
            <StackPanel Orientation="Horizontal" Margin="0 2 0 0">
                <Image Source="{Binding ImageSource}" Width="16" Height="16" Margin="0 0 3 0" />
                <TextBlock Text="{Binding Name}" />
            </StackPanel>
        </HierarchicalDataTemplate>
    </TreeView.Resources>
    </TreeView>
</UserControl>

谢谢

Answer 1

当您双击一个 TreeView 项目时，它将被展开。当它展开时，您的 IsExpanded 属性将因您的绑定(bind)而改变。单击当前未选择的内容将更改您的 IsSelected 属性。但是，再次单击它(不是双击)不会更改 IsSelected 属性。似乎您想要做的是还添加一个“点击”事件处理程序。这样，每次单击它时，您都会收到通知，而不仅仅是在第一次单击它时选择了其他内容。

要完成此操作，请将“MouseDoubleClick”事件添加到您的 TreeViewItem 样式中。如果您想要单击，只需对“MouseDown”事件执行相同操作:

<Style TargetType="{x:Type TreeViewItem}">
    <Setter Property="IsSelected" Value="{Binding Path=IsSelected, Mode=TwoWay}"/>
    <Setter Property="IsExpanded" Value="{Binding Path=IsExpanded, Mode=TwoWay}" />
    <EventSetter Event="MouseDoubleClick" Handler="DoubleClickedItem"/>
</Style>

一旦您的 XAML 中包含上面的代码，右键单击“DoubleClickedItem”一词并选择“NavigateToHandler”选项，Visual Studio 将在您的代码中为您生成一个方法 stub 。然后，您可以在那里实现您的双击行为。