如何解决WPF TreeView更改ToggleButton的背景色
<UserControl ...>
<TreeView Background="Yellow" ... >
<TreeView.Resources >
<HierarchicalDataTemplate ... >
<Grid Name="Header" Background="Green" ... >
</Grid>
</HierarchicalDataTemplate>
<DataTemplate ... >
<Grid Name="MultipleItems">
</Grid>
</DataTemplate>
</TreeView.Resources>
</TreeView>
</UserControl>
我只需要更改TreeView切换按钮的背景颜色 类似于Grid标头的Green。切换按钮的默认背景颜色类似于TreeView的黄色。
当我尝试在 TreeView 标记之后和 TreeView.Resources 标记之前添加这些代码时,遇到错误:
<TreeViewItem>
<TreeViewItem.Template>
<ControlTemplate targettype="TreeViewItem">
<Grid>
<ToggleButton>
<ToggleButton.Style>
<Style targettype="ToggleButton">
<Setter Property="Background" Value="Green"/>
</Style>
</ToggleButton.Style>
</ToggleButton>
</Grid>
</ControlTemplate>
</TreeViewItem.Template>
</TreeViewItem>
错误为“在使用ItemsSource之前,Items集合必须为空。” 。 如何成功更改切换按钮的背景颜色? 我上面的解决方法不正确吗?请告诉我是否还有其他方法 以及如何做到这一点。
<TreeViewItem></TreeViewItem>
解决方法
要更改控件的外观或视觉状态,必须更改其样式或控件模板。这些远远超出您的预期。像您提供的控件模板一样,缺少大多数状态和必需的部分(模板中的控件)才能正常工作。您可以查看所需的零件和状态in the documentation。
您可以extract the default ones using Blend or Visual Studio并使它们适应您的需求,而不是从头开始为控件创建控件模板和样式。在大多数情况下,您将复制大量代码,并且满足您的要求所需的更改很小,但是没有其他方法,因为您无法像使用样式一样将控件模板基于其他控件模板。
错误是“在使用ItemsSource之前,Items集合必须为空。”
由于在TreeViewItem
中设置了TreeView
,因此出现此错误。它将把此项添加为内容,但是由于您可能已经在其他位置设置了ItemsSource
,因此会引发错误,因为您不能同时执行这两项。相反,您可以通过ItemContainerStyle
属性设置自定义样式,例如像这样的内联:
<TreeView ItemsSource="{Binding MyTreeViewNodes}">
<TreeView.ItemContainerStyle>
<Style TargetType="{x:Type TreeViewItem}">
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="TreeViewItem">
<!-- ...your control template -->
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</TreeView.ItemContainerStyle>
<!-- ...other tree view definitions. -->
</TreeView>
当然,您也可以使用StaticResource
或DynamicResource
引用命名样式。希望您能理解,但无论哪种方式,您的控制模板都不完整,无法正常工作。
我已经提取了包括TreeViewItem
的控制模板在内的默认样式,并对其进行了调整。您必须将所有这些样式复制到范围或应用程序资源中的资源字典中。
<SolidColorBrush x:Key="TreeViewItem.TreeArrow.Static.Background" Color="Green"/>
<SolidColorBrush x:Key="TreeViewItem.TreeArrow.Static.Stroke" Color="#FF818181"/>
<SolidColorBrush x:Key="TreeViewItem.TreeArrow.Static.Fill" Color="#FFFFFFFF"/>
<SolidColorBrush x:Key="TreeViewItem.TreeArrow.MouseOver.Background" Color="Green"/>
<SolidColorBrush x:Key="TreeViewItem.TreeArrow.MouseOver.Stroke" Color="#FF27C7F7"/>
<SolidColorBrush x:Key="TreeViewItem.TreeArrow.MouseOver.Fill" Color="#FFCCEEFB"/>
<SolidColorBrush x:Key="TreeViewItem.TreeArrow.Static.Checked.Background" Color="Green"/>
<SolidColorBrush x:Key="TreeViewItem.TreeArrow.Static.Checked.Stroke" Color="#FF262626"/>
<SolidColorBrush x:Key="TreeViewItem.TreeArrow.Static.Checked.Fill" Color="#FF595959"/>
<SolidColorBrush x:Key="TreeViewItem.TreeArrow.MouseOver.Checked.Background" Color="Green"/>
<SolidColorBrush x:Key="TreeViewItem.TreeArrow.MouseOver.Checked.Stroke" Color="#FF1CC4F7"/>
<SolidColorBrush x:Key="TreeViewItem.TreeArrow.MouseOver.Checked.Fill" Color="#FF82DFFB"/>
<PathGeometry x:Key="TreeArrow" Figures="M0,0 L0,6 L6,0 z"/>
<Style x:Key="ExpandCollapseToggleStyle" TargetType="{x:Type ToggleButton}">
<Setter Property="Focusable" Value="False"/>
<Setter Property="Width" Value="16"/>
<Setter Property="Height" Value="16"/>
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type ToggleButton}">
<Border x:Name="ExpandBorder" Background="{StaticResource TreeViewItem.TreeArrow.Static.Background}" Height="16" Padding="5,5,5" Width="16">
<Path x:Name="ExpandPath" Data="{StaticResource TreeArrow}" Fill="{StaticResource TreeViewItem.TreeArrow.Static.Fill}" Stroke="{StaticResource TreeViewItem.TreeArrow.Static.Stroke}">
<Path.RenderTransform>
<RotateTransform Angle="135" CenterY="3" CenterX="3"/>
</Path.RenderTransform>
</Path>
</Border>
<ControlTemplate.Triggers>
<Trigger Property="IsChecked" Value="True">
<Setter Property="RenderTransform" TargetName="ExpandPath">
<Setter.Value>
<RotateTransform Angle="180" CenterY="3" CenterX="3"/>
</Setter.Value>
</Setter>
<Setter Property="Fill" TargetName="ExpandPath" Value="{StaticResource TreeViewItem.TreeArrow.Static.Checked.Fill}"/>
<Setter Property="Stroke" TargetName="ExpandPath" Value="{StaticResource TreeViewItem.TreeArrow.Static.Checked.Stroke}"/>
<Setter Property="Background" TargetName="ExpandBorder" Value="{StaticResource TreeViewItem.TreeArrow.Static.Checked.Background}"/>
</Trigger>
<Trigger Property="IsMouseOver" Value="True">
<Setter Property="Stroke" TargetName="ExpandPath" Value="{StaticResource TreeViewItem.TreeArrow.MouseOver.Stroke}"/>
<Setter Property="Fill" TargetName="ExpandPath" Value="{StaticResource TreeViewItem.TreeArrow.MouseOver.Fill}"/>
<Setter Property="Background" TargetName="ExpandBorder" Value="{StaticResource TreeViewItem.TreeArrow.MouseOver.Background}"/>
</Trigger>
<MultiTrigger>
<MultiTrigger.Conditions>
<Condition Property="IsMouseOver" Value="True"/>
<Condition Property="IsChecked" Value="True"/>
</MultiTrigger.Conditions>
<Setter Property="Stroke" TargetName="ExpandPath" Value="{StaticResource TreeViewItem.TreeArrow.MouseOver.Checked.Stroke}"/>
<Setter Property="Fill" TargetName="ExpandPath" Value="{StaticResource TreeViewItem.TreeArrow.MouseOver.Checked.Fill}"/>
<Setter Property="Background" TargetName="ExpandBorder" Value="{StaticResource TreeViewItem.TreeArrow.MouseOver.Checked.Background}"/>
</MultiTrigger>
</ControlTemplate.Triggers>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
<Style x:Key="TreeViewItemFocusVisual">
<Setter Property="Control.Template">
<Setter.Value>
<ControlTemplate>
<Rectangle/>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
<Style x:Key="TreeViewItemContainerStyle" TargetType="{x:Type TreeViewItem}">
<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"/>
<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>
<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" ClickMode="Press" IsChecked="{Binding IsExpanded,RelativeSource={RelativeSource TemplatedParent}}" Style="{StaticResource ExpandCollapseToggleStyle}"/>
<Border x:Name="Bd" Background="{TemplateBinding Background}" BorderThickness="{TemplateBinding BorderThickness}" BorderBrush="{TemplateBinding BorderBrush}" Grid.Column="1" Padding="{TemplateBinding Padding}" SnapsToDevicePixels="true">
<ContentPresenter x:Name="PART_Header" ContentSource="Header" HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
</Border>
<ItemsPresenter x:Name="ItemsHost" Grid.ColumnSpan="2" Grid.Column="1" Grid.Row="1"/>
</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="Background" TargetName="Bd" Value="{DynamicResource {x:Static SystemColors.HighlightBrushKey}}"/>
<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" TargetName="Bd" Value="{DynamicResource {x:Static SystemColors.InactiveSelectionHighlightBrushKey}}"/>
<Setter Property="Foreground" Value="{DynamicResource {x:Static SystemColors.InactiveSelectionHighlightTextBrushKey}}"/>
</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="VirtualizingPanel.IsVirtualizing" Value="true">
<Setter Property="ItemsPanel">
<Setter.Value>
<ItemsPanelTemplate>
<VirtualizingStackPanel/>
</ItemsPanelTemplate>
</Setter.Value>
</Setter>
</Trigger>
</Style.Triggers>
</Style>
如您所见,这非常复杂。项目本身中有TreeViewItem
的样式,焦点样式和ToggleButton
的样式。我只改编了名为Border
的{{1}}并为其分配了初始背景,具体取决于触发器中项目的状态。
如果要在不同状态下调整颜色,只需更改以下画笔即可:
-
ExpandBorder
-
TreeViewItem.TreeArrow.Static.Background
-
TreeViewItem.TreeArrow.MouseOver.Background
-
TreeViewItem.TreeArrow.Static.Checked.Background
要应用新的TreeViewItem.TreeArrow.MouseOver.Checked.Background
样式,请将其引用为TreeViewItem
。
ItemContainerStyle
如果省略相应样式的键,则可以将样式应用于范围中的所有<TreeView ItemsSource="{Binding MyTreeViewNodes}" ItemContainerStyle="{StaticResource TreeViewItemContainerStyle}">
,这使其成为隐式样式。
TreeViewItem
,
您的某些代码用省略号隐藏了,但我的猜测是,当已经指定了<TreeViewItem/>
属性时,您正在尝试将TreeView.Items
添加到TreeView.ItemSource
。使用ItemsControl时,必须使用Items属性或ItemsSource属性。
请查看this 这样的答案以了解更多详细信息。
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