是否可以在装饰层之上绘制 UI 元素？
Is It Possible To Draw a UI Element On Top of the Adorner Layer?
对于我的 WPF TreeView 用户控件，我想在 ToggleButton 周围显示一个进度环，以指示节点的子节点正在填充，如下所示：
（完全公开，我在一些开源软件中看到了这种行为，我只是不记得在哪里）。我仍然希望切换按钮是交互式的（即获取鼠标事件，如悬停和单击），以便用户在不想等待更新完成时可以折叠节点。
我的第一个想法是将进度环作为装饰层添加到 ToggleButton。但是，由于 WPF 装饰层位于 Z 顺序中 UI 元素的顶部，我似乎无法与进度环下方的切换按钮进行交互。有没有办法在装饰层的顶部绘制切换按钮？或者在这种情况下装饰层似乎不是正确的方法？在更新子项时，只触发一个 属性 来控制切换按钮的模板并绘制进度环和切换按钮会更好吗？感谢您的任何想法！
我正在利用的相关教程：
Working with Checkboxes in the WPF TreeView
WPF Loading Wait Adorner（包含进度环和装饰品来源的链接）
您可以使用网格在扩展器（切换按钮）后面添加动画。 Grid 将按 z 顺序将元素堆叠在同一单元格中。动画可以始终存在，只是隐藏起来，通过您定义的某个触发器使其可见。
我相信你不需要装饰品来完成你想要的。
我已经通过 Blend 编辑了树视图模板，将带有忙碌动画的用户控件添加到树视图项目样式的扩展器按钮中。有很多工作要做，但它可以向您展示方法。也可能有更好的方法来改变指示器的可见性，而不是在可视化树中搜索它。
我的看法是为treeview 和treeviewitem 创建自定义控件。覆盖它的样式并为 treeviewitem 添加 "IsLoading" 属性。切换这个 属性 应该会改变用户控件的可见性。
MainWindow.xaml
<Window x:Class="WpfApplication17.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="MainWindow" Height="350" Width="525" xmlns:local="clr-namespace:WpfApplication17">
<Window.Resources>
<Style x:Key="TreeViewItemFocusVisual">
<Setter Property="Control.Template">
<Setter.Value>
<ControlTemplate>
<Rectangle/>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
<SolidColorBrush x:Key="TreeViewItem.TreeArrow.Static.Checked.Fill" Color="#FF595959"/>
<SolidColorBrush x:Key="TreeViewItem.TreeArrow.Static.Checked.Stroke" Color="#FF262626"/>
<SolidColorBrush x:Key="TreeViewItem.TreeArrow.MouseOver.Stroke" Color="#FF1BBBFA"/>
<SolidColorBrush x:Key="TreeViewItem.TreeArrow.MouseOver.Fill" Color="Transparent"/>
<SolidColorBrush x:Key="TreeViewItem.TreeArrow.MouseOver.Checked.Stroke" Color="#FF262626"/>
<SolidColorBrush x:Key="TreeViewItem.TreeArrow.MouseOver.Checked.Fill" Color="#FF595959"/>
<PathGeometry x:Key="TreeArrow" Figures="M0,0 L0,6 L6,0 z"/>
<SolidColorBrush x:Key="TreeViewItem.TreeArrow.Static.Fill" Color="Transparent"/>
<SolidColorBrush x:Key="TreeViewItem.TreeArrow.Static.Stroke" Color="#FF989898"/>
<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}">
<Grid HorizontalAlignment="Left" Height="16" VerticalAlignment="Top" Width="16">
<Border Background="Transparent" Height="16" Padding="5,5,5,5" 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>
<local:UserControl1 Name="busyInd"/>
</Grid>
<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}"/>
</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}"/>
</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}"/>
</MultiTrigger>
</ControlTemplate.Triggers>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
<Style x:Key="TreeViewItemStyle1" 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="1,0,0,0"/>
<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>
<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" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}" 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>
<Style x:Key="BusyInd" TargetType="{x:Type Grid}"/>
</Window.Resources>
<Grid>
<TreeView Name="treeView" SelectedItemChanged="treeView_SelectedItemChanged" HorizontalAlignment="Left" Height="300" Margin="10,10,0,0" VerticalAlignment="Top" Width="497" ItemContainerStyle="{DynamicResource TreeViewItemStyle1}">
<TreeViewItem Header="TreeViewItem" IsExpanded="True">
<TreeViewItem Header="TreeViewItem" HorizontalAlignment="Left" Width="474"/>
<TreeViewItem Header="TreeViewItem" HorizontalAlignment="Left" Width="474"/>
</TreeViewItem>
<TreeViewItem Header="TreeViewItem" IsExpanded="True">
<TreeViewItem Header="TreeViewItem" HorizontalAlignment="Left" Width="474"/>
<TreeViewItem Header="TreeViewItem" HorizontalAlignment="Left" Width="474"/>
</TreeViewItem>
<TreeViewItem Header="TreeViewItem" IsExpanded="True">
<TreeViewItem Header="TreeViewItem" HorizontalAlignment="Left" Width="474"/>
</TreeViewItem>
</TreeView>
</Grid>
</Window>
MainWindow.cs
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
}
private void treeView_SelectedItemChanged(object sender, RoutedPropertyChangedEventArgs<object> e)
{
TreeViewItem item_container = (TreeViewItem)treeView.ItemContainerGenerator.ContainerFromItem(treeView.SelectedItem);
var indicator = FindChild<UserControl1>(item_container, "busyInd");
indicator.Visibility = Visibility.Visible;
Task.Factory.StartNew(() =>
{
Thread.Sleep(3000);
Dispatcher.Invoke(() => { indicator.Visibility = Visibility.Collapsed; });
});
}
public static T FindChild<T>(DependencyObject parent, string childName)
where T : DependencyObject
{
if (parent == null) return null;
T foundChild = null;
int childrenCount = VisualTreeHelper.GetChildrenCount(parent);
for (int i = 0; i < childrenCount; i++)
{
var child = VisualTreeHelper.GetChild(parent, i);
// If the child is not of the request child type child
T childType = child as T;
if (childType == null)
{
// recursively drill down the tree
foundChild = FindChild<T>(child, childName);
// If the child is found, break so we do not overwrite the found child.
if (foundChild != null) break;
}
else if (!string.IsNullOrEmpty(childName))
{
var frameworkElement = child as FrameworkElement;
// If the child's name is set for search
if (frameworkElement != null && frameworkElement.Name == childName)
{
// if the child's name is of the request name
foundChild = (T)child;
break;
}
}
else
{
// child element found.
foundChild = (T)child;
break;
}
}
return foundChild;
}
}
UserControl1.xaml
<UserControl x:Class="WpfApplication17.UserControl1"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Height="Auto" Width="Auto" Background="Transparent" Visibility="Collapsed">
<Viewbox Width="{Binding Width, ElementName=BusyIndicator}" Height="{Binding Height, ElementName=BusyIndicator}"
HorizontalAlignment="Center" VerticalAlignment="Center">
<Grid Background="Transparent" ToolTip="Searching...." HorizontalAlignment="Center" VerticalAlignment="Center">
<Canvas Name="Canvas1"
RenderTransformOrigin="0.5,0.5"
HorizontalAlignment="Center"
VerticalAlignment="Center" Width="120" Height="120">
<Canvas.RenderTransform>
<RotateTransform Angle="0" />
</Canvas.RenderTransform>
<Canvas.Style>
<Style TargetType="Canvas">
<Style.Triggers>
<Trigger Property="IsVisible" Value="True">
<Trigger.EnterActions>
<BeginStoryboard Name="Storyboard_Rotate">
<Storyboard RepeatBehavior="Forever">
<DoubleAnimation Storyboard.TargetProperty="RenderTransform.Angle"
From="0" To="360" Duration="0:0:2"/>
</Storyboard>
</BeginStoryboard>
</Trigger.EnterActions>
<Trigger.ExitActions>
<StopStoryboard BeginStoryboardName="Storyboard_Rotate" />
</Trigger.ExitActions>
</Trigger>
</Style.Triggers>
</Style>
</Canvas.Style>
<Ellipse Width="20" Height="20" Stretch="Fill" Fill="Black" Opacity="1.0" Canvas.Left="50" Canvas.Top="0" />
<Ellipse Width="20" Height="20" Stretch="Fill" Fill="Black" Opacity="0.9" Canvas.Left="20.6107373853764" Canvas.Top="9.54915028125262" />
<Ellipse Width="20" Height="20" Stretch="Fill" Fill="Black" Opacity="0.8" Canvas.Left="2.44717418524233" Canvas.Top="34.5491502812526" />
<Ellipse Width="20" Height="20" Stretch="Fill" Fill="Black" Opacity="0.7" Canvas.Left="2.44717418524232" Canvas.Top="65.4508497187474" />
<Ellipse Width="20" Height="20" Stretch="Fill" Fill="Black" Opacity="0.6" Canvas.Left="20.6107373853763" Canvas.Top="90.4508497187474" />
<Ellipse Width="20" Height="20" Stretch="Fill" Fill="Black" Opacity="0.5" Canvas.Left="50" Canvas.Top="100" />
<Ellipse Width="20" Height="20" Stretch="Fill" Fill="Black" Opacity="0.4" Canvas.Left="79.3892626146236" Canvas.Top="90.4508497187474" />
<Ellipse Width="20" Height="20" Stretch="Fill" Fill="Black" Opacity="0.3" Canvas.Left="97.5528258147577" Canvas.Top="65.4508497187474" />
<Ellipse Width="20" Height="20" Stretch="Fill" Fill="Black" Opacity="0.2" Canvas.Left="97.5528258147577" Canvas.Top="34.5491502812526" />
</Canvas>
</Grid>
</Viewbox>
</UserControl>
对于我的 WPF TreeView 用户控件，我想在 ToggleButton 周围显示一个进度环，以指示节点的子节点正在填充，如下所示：
（完全公开，我在一些开源软件中看到了这种行为，我只是不记得在哪里）。我仍然希望切换按钮是交互式的（即获取鼠标事件，如悬停和单击），以便用户在不想等待更新完成时可以折叠节点。
我的第一个想法是将进度环作为装饰层添加到 ToggleButton。但是，由于 WPF 装饰层位于 Z 顺序中 UI 元素的顶部，我似乎无法与进度环下方的切换按钮进行交互。有没有办法在装饰层的顶部绘制切换按钮？或者在这种情况下装饰层似乎不是正确的方法？在更新子项时，只触发一个 属性 来控制切换按钮的模板并绘制进度环和切换按钮会更好吗？感谢您的任何想法！
我正在利用的相关教程：
Working with Checkboxes in the WPF TreeView
WPF Loading Wait Adorner（包含进度环和装饰品来源的链接）
您可以使用网格在扩展器（切换按钮）后面添加动画。 Grid 将按 z 顺序将元素堆叠在同一单元格中。动画可以始终存在，只是隐藏起来，通过您定义的某个触发器使其可见。
我相信你不需要装饰品来完成你想要的。 我已经通过 Blend 编辑了树视图模板，将带有忙碌动画的用户控件添加到树视图项目样式的扩展器按钮中。有很多工作要做，但它可以向您展示方法。也可能有更好的方法来改变指示器的可见性，而不是在可视化树中搜索它。
我的看法是为treeview 和treeviewitem 创建自定义控件。覆盖它的样式并为 treeviewitem 添加 "IsLoading" 属性。切换这个 属性 应该会改变用户控件的可见性。
MainWindow.xaml
<Window x:Class="WpfApplication17.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="MainWindow" Height="350" Width="525" xmlns:local="clr-namespace:WpfApplication17">
<Window.Resources>
<Style x:Key="TreeViewItemFocusVisual">
<Setter Property="Control.Template">
<Setter.Value>
<ControlTemplate>
<Rectangle/>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
<SolidColorBrush x:Key="TreeViewItem.TreeArrow.Static.Checked.Fill" Color="#FF595959"/>
<SolidColorBrush x:Key="TreeViewItem.TreeArrow.Static.Checked.Stroke" Color="#FF262626"/>
<SolidColorBrush x:Key="TreeViewItem.TreeArrow.MouseOver.Stroke" Color="#FF1BBBFA"/>
<SolidColorBrush x:Key="TreeViewItem.TreeArrow.MouseOver.Fill" Color="Transparent"/>
<SolidColorBrush x:Key="TreeViewItem.TreeArrow.MouseOver.Checked.Stroke" Color="#FF262626"/>
<SolidColorBrush x:Key="TreeViewItem.TreeArrow.MouseOver.Checked.Fill" Color="#FF595959"/>
<PathGeometry x:Key="TreeArrow" Figures="M0,0 L0,6 L6,0 z"/>
<SolidColorBrush x:Key="TreeViewItem.TreeArrow.Static.Fill" Color="Transparent"/>
<SolidColorBrush x:Key="TreeViewItem.TreeArrow.Static.Stroke" Color="#FF989898"/>
<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}">
<Grid HorizontalAlignment="Left" Height="16" VerticalAlignment="Top" Width="16">
<Border Background="Transparent" Height="16" Padding="5,5,5,5" 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>
<local:UserControl1 Name="busyInd"/>
</Grid>
<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}"/>
</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}"/>
</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}"/>
</MultiTrigger>
</ControlTemplate.Triggers>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
<Style x:Key="TreeViewItemStyle1" 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="1,0,0,0"/>
<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>
<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" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}" 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>
<Style x:Key="BusyInd" TargetType="{x:Type Grid}"/>
</Window.Resources>
<Grid>
<TreeView Name="treeView" SelectedItemChanged="treeView_SelectedItemChanged" HorizontalAlignment="Left" Height="300" Margin="10,10,0,0" VerticalAlignment="Top" Width="497" ItemContainerStyle="{DynamicResource TreeViewItemStyle1}">
<TreeViewItem Header="TreeViewItem" IsExpanded="True">
<TreeViewItem Header="TreeViewItem" HorizontalAlignment="Left" Width="474"/>
<TreeViewItem Header="TreeViewItem" HorizontalAlignment="Left" Width="474"/>
</TreeViewItem>
<TreeViewItem Header="TreeViewItem" IsExpanded="True">
<TreeViewItem Header="TreeViewItem" HorizontalAlignment="Left" Width="474"/>
<TreeViewItem Header="TreeViewItem" HorizontalAlignment="Left" Width="474"/>
</TreeViewItem>
<TreeViewItem Header="TreeViewItem" IsExpanded="True">
<TreeViewItem Header="TreeViewItem" HorizontalAlignment="Left" Width="474"/>
</TreeViewItem>
</TreeView>
</Grid>
</Window>
MainWindow.cs
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
}
private void treeView_SelectedItemChanged(object sender, RoutedPropertyChangedEventArgs<object> e)
{
TreeViewItem item_container = (TreeViewItem)treeView.ItemContainerGenerator.ContainerFromItem(treeView.SelectedItem);
var indicator = FindChild<UserControl1>(item_container, "busyInd");
indicator.Visibility = Visibility.Visible;
Task.Factory.StartNew(() =>
{
Thread.Sleep(3000);
Dispatcher.Invoke(() => { indicator.Visibility = Visibility.Collapsed; });
});
}
public static T FindChild<T>(DependencyObject parent, string childName)
where T : DependencyObject
{
if (parent == null) return null;
T foundChild = null;
int childrenCount = VisualTreeHelper.GetChildrenCount(parent);
for (int i = 0; i < childrenCount; i++)
{
var child = VisualTreeHelper.GetChild(parent, i);
// If the child is not of the request child type child
T childType = child as T;
if (childType == null)
{
// recursively drill down the tree
foundChild = FindChild<T>(child, childName);
// If the child is found, break so we do not overwrite the found child.
if (foundChild != null) break;
}
else if (!string.IsNullOrEmpty(childName))
{
var frameworkElement = child as FrameworkElement;
// If the child's name is set for search
if (frameworkElement != null && frameworkElement.Name == childName)
{
// if the child's name is of the request name
foundChild = (T)child;
break;
}
}
else
{
// child element found.
foundChild = (T)child;
break;
}
}
return foundChild;
}
}
UserControl1.xaml
<UserControl x:Class="WpfApplication17.UserControl1"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Height="Auto" Width="Auto" Background="Transparent" Visibility="Collapsed">
<Viewbox Width="{Binding Width, ElementName=BusyIndicator}" Height="{Binding Height, ElementName=BusyIndicator}"
HorizontalAlignment="Center" VerticalAlignment="Center">
<Grid Background="Transparent" ToolTip="Searching...." HorizontalAlignment="Center" VerticalAlignment="Center">
<Canvas Name="Canvas1"
RenderTransformOrigin="0.5,0.5"
HorizontalAlignment="Center"
VerticalAlignment="Center" Width="120" Height="120">
<Canvas.RenderTransform>
<RotateTransform Angle="0" />
</Canvas.RenderTransform>
<Canvas.Style>
<Style TargetType="Canvas">
<Style.Triggers>
<Trigger Property="IsVisible" Value="True">
<Trigger.EnterActions>
<BeginStoryboard Name="Storyboard_Rotate">
<Storyboard RepeatBehavior="Forever">
<DoubleAnimation Storyboard.TargetProperty="RenderTransform.Angle"
From="0" To="360" Duration="0:0:2"/>
</Storyboard>
</BeginStoryboard>
</Trigger.EnterActions>
<Trigger.ExitActions>
<StopStoryboard BeginStoryboardName="Storyboard_Rotate" />
</Trigger.ExitActions>
</Trigger>
</Style.Triggers>
</Style>
</Canvas.Style>
<Ellipse Width="20" Height="20" Stretch="Fill" Fill="Black" Opacity="1.0" Canvas.Left="50" Canvas.Top="0" />
<Ellipse Width="20" Height="20" Stretch="Fill" Fill="Black" Opacity="0.9" Canvas.Left="20.6107373853764" Canvas.Top="9.54915028125262" />
<Ellipse Width="20" Height="20" Stretch="Fill" Fill="Black" Opacity="0.8" Canvas.Left="2.44717418524233" Canvas.Top="34.5491502812526" />
<Ellipse Width="20" Height="20" Stretch="Fill" Fill="Black" Opacity="0.7" Canvas.Left="2.44717418524232" Canvas.Top="65.4508497187474" />
<Ellipse Width="20" Height="20" Stretch="Fill" Fill="Black" Opacity="0.6" Canvas.Left="20.6107373853763" Canvas.Top="90.4508497187474" />
<Ellipse Width="20" Height="20" Stretch="Fill" Fill="Black" Opacity="0.5" Canvas.Left="50" Canvas.Top="100" />
<Ellipse Width="20" Height="20" Stretch="Fill" Fill="Black" Opacity="0.4" Canvas.Left="79.3892626146236" Canvas.Top="90.4508497187474" />
<Ellipse Width="20" Height="20" Stretch="Fill" Fill="Black" Opacity="0.3" Canvas.Left="97.5528258147577" Canvas.Top="65.4508497187474" />
<Ellipse Width="20" Height="20" Stretch="Fill" Fill="Black" Opacity="0.2" Canvas.Left="97.5528258147577" Canvas.Top="34.5491502812526" />
</Canvas>
</Grid>
</Viewbox>
</UserControl>