问题描述
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的子级.我正在启用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中.现在，除了一件事以外，其他所有东西都在工作.我的DragDropHelper类需要在ItemsPresenter(或相关类)中指定该控件是拖动源还是放置目标.
I have two classes that are represented in a TreeView. DiskSpec and DiskSet. DiskSpec can exist by itself, or it can be a child of DiskSet. I am working on enabling DragDrop functionality so that the user can drag a DiskSpec from the DiskSpec node onto a DiskSet to add it to that DiskSet. Now all is working except for one thing. My DragDropHelper class needs to specify in an ItemsPresenter (or related class) that that control is a drag source or a drop target.
我的TreeView设置如下:.
My TreeView is set up like so: .
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为DropTarget)，一次用于其他所有条件，指定其ItemsPresenter为DragSource.
So I really need to have two TreeViewItem Styles. Once for DiskSets (which specifies that the ItemsPresenter that will present the DiskSpecs is a DropTarget) and one for everything else which specifies that it's ItemsPresenter is a DragSource.
不幸的是，我还没有从HierarchicalDataTemplate对象中看到任何设置TreeViewItem样式或模板的方法，并且似乎没有一种方法可以指定此ItemTemplate仅用于特定的DataType.
Unfortunately I have not seen any way to set the TreeViewItem Style or Template from the HierarchicalDataTemplate object, and there does not appear to be a way to specify that this ItemTemplate is only for a particular DataType.
有什么想法吗?还是我错过了什么?
Any thoughts? Or am I missing something?
从我的XAML中找到一些示例.
Find below some samples from my XAML.
有关DragDropHelper属性设置的示例，请参见ItemsPresenter部分.
See the ItemsPresenter section for an example of the DragDropHelper properties settings.
<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的博客文章:如何在数据绑定之间拖放项目ItemsControls?
推荐答案
为什么需要TreeViewItem的样式?只能使用DataTemplates完成此操作，如果您希望它们自动应用，则不要指定键.
Why do you need a style for a TreeViewItem?It can be done using DataTemplates only, and don't specify a key if you want them to apply automatically.
<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"模板中启用拖放，然后在设置"模板中拖放.
After that you can enable drag in the Disk template and drop in the Set template.
这篇关于如何为从HierarchicalDataTemplate生成的TreeViewItem指定哪种TreeViewItem样式/模板?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！