情况：

Question

情况：

我有两个在TreeView中表示的类。 DiskSpec和DiskSet。 DiskSpec可以单独存在，也可以是DiskSet的子节点。我正在努力启用DragDrop功能，以便用户可以将DiskSpec从DiskSpec节点拖到DiskSet上，以将其添加到该DiskSet。现在一切正常，除了一件事。我的DragDropHelper类需要在ItemsPresenter（或相关类）中指定该控件是拖动源或放置目标。

我的TreeView设置如下：。

问题：

所以我真的需要两个TreeViewItem样式。一次用于DiskSets（指定将显示DiskSpecs的ItemsPresenter是DropTarget），另一个用于指定其ItemsPresenter是DragSource的其他内容。

不幸的是，我没有看到任何方法从HierarchicalDataTemplate对象设置TreeViewItem样式或模板，并且似乎没有办法指定此ItemTemplate仅用于特定的DataType。

有什么想法？或者我错过了什么？

在下面找到我的XAML中的一些样本。

默认TreeViewItem

有关DragDropHelper属性设置的示例，请参阅ItemsPresenter部分。

<Style TargetType="{x:Type TreeViewItem}">
    <Setter Property="IsExpanded" Value="{Binding IsExpanded, Mode=TwoWay}"/>
    <Setter Property="Background" Value="Transparent"/>
    <Setter Property="HorizontalContentAlignment" Value="{Binding HorizontalContentAlignment, RelativeSource={RelativeSource AncestorType={x:Type ItemsControl}}}"/>
    <Setter Property="VerticalContentAlignment" Value="{Binding VerticalContentAlignment, RelativeSource={RelativeSource AncestorType={x:Type ItemsControl}}}"/>
    <Setter Property="Padding" Value="1,0,0,0"/>
    <Setter Property="Foreground" Value="{DynamicResource {x:Static SystemColors.ControlTextBrushKey}}"/>
    <Setter Property="FocusVisualStyle" Value="{StaticResource TreeViewItemFocusVisual}"/>
    <Setter Property="Template">
        <Setter.Value>
            <ControlTemplate TargetType="{x:Type TreeViewItem}">
                <Grid Margin="0,4,0,0">
                    <Grid.ColumnDefinitions>
                        <ColumnDefinition Width="Auto" MinWidth="10"/>
                        <ColumnDefinition Width="*"/>
                    </Grid.ColumnDefinitions>
                    <Grid.RowDefinitions>
                        <RowDefinition Height="Auto" MinHeight="27.75"/>
                        <RowDefinition/>
                    </Grid.RowDefinitions>
                    <ToggleButton x:Name="Expander" ClickMode="Press" IsChecked="{Binding IsExpanded, RelativeSource={RelativeSource TemplatedParent}}" BorderBrush="#00376206" Foreground="#00000000" Style="{DynamicResource ToggleButtonStyle1}" Grid.Column="1">
                        <ToggleButton.Background>
                            <LinearGradientBrush EndPoint="0.5,1" StartPoint="0.5,0">
                                <GradientStop Color="White" Offset="0"/>
                                <GradientStop Color="#00F3EEDB" Offset="0.9"/>
                            </LinearGradientBrush>
                        </ToggleButton.Background>
                    </ToggleButton>
                    <Border x:Name="Bd" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Grid.Column="0" Padding="{TemplateBinding Padding}" SnapsToDevicePixels="true" Grid.ColumnSpan="2" CornerRadius="7" Height="26" VerticalAlignment="Top" Margin="0,0,8,0" Background="#59000000">
                        <ContentPresenter x:Name="PART_Header" ContentSource="Header" HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" Margin="5,3,0,3" VerticalAlignment="Center"/>
                    </Border>
                    <ItemsPresenter x:Name="ItemsHost" Grid.ColumnSpan="2" Grid.Column="1" Grid.Row="1" drag:DragDropHelper.IsDropTarget="False" />
                </Grid>
                <ControlTemplate.Triggers>
                    <Trigger Property="IsExpanded" Value="false">
                        <Setter Property="Visibility" TargetName="ItemsHost" Value="Collapsed"/>
                    </Trigger>
                    <Trigger Property="HasItems" Value="false">
                        <Setter Property="Visibility" TargetName="Expander" Value="Hidden"/>
                    </Trigger>
                    <Trigger Property="IsSelected" Value="true">
                        <Setter Property="BitmapEffect" TargetName="Bd">
                            <Setter.Value>
                                <DropShadowBitmapEffect />
                            </Setter.Value>
                        </Setter>
                        <Setter Property="Foreground" Value="{DynamicResource {x:Static SystemColors.HighlightTextBrushKey}}"/>
                        <Setter Property="Background" TargetName="Bd">
                            <Setter.Value>
                                <LinearGradientBrush EndPoint="0.5,1" StartPoint="0.5,0">
                                    <GradientStop Color="#FF5C5C5C" Offset="0.27"/>
                                    <GradientStop Color="#FF585858" Offset="1"/>
                                    <GradientStop Color="#FF747474" Offset="0"/>
                                </LinearGradientBrush>
                            </Setter.Value>
                        </Setter>
                    </Trigger>
                    <MultiTrigger>
                        <MultiTrigger.Conditions>
                            <Condition Property="IsSelected" Value="true"/>
                            <Condition Property="IsSelectionActive" Value="false"/>
                        </MultiTrigger.Conditions>
                        <Setter Property="Background" TargetName="Bd" Value="{DynamicResource {x:Static SystemColors.ControlBrushKey}}"/>
                        <Setter Property="Foreground" Value="{DynamicResource {x:Static SystemColors.ControlTextBrushKey}}"/>
                    </MultiTrigger>
                    <Trigger Property="IsEnabled" Value="false">
                        <Setter Property="Foreground" Value="{DynamicResource {x:Static SystemColors.GrayTextBrushKey}}"/>
                    </Trigger>
                </ControlTemplate.Triggers>
            </ControlTemplate>
        </Setter.Value>
    </Setter>
    <Style.Triggers>
        <Trigger Property="VirtualizingStackPanel.IsVirtualizing" Value="true">
            <Setter Property="ItemsPanel">
                <Setter.Value>
                    <ItemsPanelTemplate>
                        <VirtualizingStackPanel/>
                    </ItemsPanelTemplate>
                </Setter.Value>
            </Setter>
        </Trigger>
    </Style.Triggers>
</Style>

TreeView结构

<TreeView x:Name="treeView" Margin="4,40,4,4" Style="{DynamicResource SnazzyTreeView}" >
    <TreeView.Resources>

    </TreeView.Resources>
    <TreeViewItem ItemsSource="{Binding Disks}" IsExpanded="True" drag:DragDropHelper.IsDragSource="True" drag:DragDropHelper.IsDropTarget="False" drag:DragDropHelper.DragDropTemplate="{StaticResource draggedDisk}">
        <TreeViewItem.Header>
            <TextBlock Text="Disks" Foreground="White" FontSize="16"/>
        </TreeViewItem.Header>
    </TreeViewItem>
    <TreeViewItem ItemsSource="{Binding DiskSets}" IsExpanded="True">
        <TreeViewItem.Header>
            <TextBlock Text="DiskSets" Foreground="White" FontSize="16"/>
        </TreeViewItem.Header>
    </TreeViewItem>
</TreeView>

Bea Stolnitz's Blog Post: How can I drag and drop items between data bound ItemsControls?

Answer 1

为什么需要TreeViewItem的样式？它可以仅使用DataTemplates完成，如果您希望自动应用它们，则不指定密钥。

<Window.Resources>
    <DataTemplate DataType = "{x:Type local:DiskSpec}">
        <TextBlock Text="{Binding Title}" drag:DragDropHelper.IsDragSource="True"
                   drag:DragDropHelper.IsDropTarget="False"/>
    </DataTemplate>

    <HierarchicalDataTemplate DataType = "{x:Type local:DiskSet}"
                            ItemsSource = "{Binding Path=Disks}">
        <TextBlock Text="{Binding Title}"/>
    </HierarchicalDataTemplate>

</Window.Resources>

tree.ItemsSource = new object[]{
            new DiskSpec{Title = "Disc 1"},
            new DiskSpec{Title = "Disc 2"},
            new DiskSet{Title = "Set 1", Disks = new List<DiskSpec>{new DiskSpec{Title="Disc 1.1"}}},
            new DiskSet{Title = "Set 2", Disks = new List<DiskSpec>{new DiskSpec{Title="Disc 2.1"}, new DiskSpec{Title="Disc 2.2"}}}};

之后，您可以在磁盘模板中启用拖动并放入设置模板。

如何为从HierarchicalDataTemplate生成的TreeViewItem指定哪个TreeViewItem样式/模板？

情况：

问题：

默认TreeViewItem

TreeView结构

1 个答案: