As in topic. I want to change view style of TreeViewItem. Without Items arrow is invisible. I want to make it visible without adding any blank item.
Don't know what you mean by
without adding any blank item
however, you can add item, but set its Visibility to Collapsed:
<TreeView>
<TreeViewItem>
<TextBlock Text="A"/>
</TreeViewItem>
<TreeViewItem>
<TextBlock Text="A" Visibility="Collapsed"/>
</TreeViewItem>
</TreeView>
Another approach:
Use this style and remove this part:
<Trigger Property="HasItems"
Value="false">
<Setter TargetName="Expander"
Property="Visibility"
Value="Hidden" />
</Trigger>
Edit
<Window x:Class="Test.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:local="clr-namespace:Test"
xmlns:scm="clr-namespace:System.ComponentModel;assembly=WindowsBase"
mc:Ignorable="d"
Title="MainWindow">
<Window.Resources>
<Color x:Key="WindowColor">#FFE8EDF9</Color>
<Color x:Key="ContentAreaColorLight">#FFC5CBF9</Color>
<Color x:Key="ContentAreaColorDark">#FF7381F9</Color>
<Color x:Key="DisabledControlLightColor">#FFE8EDF9</Color>
<Color x:Key="DisabledControlDarkColor">#FFC5CBF9</Color>
<Color x:Key="DisabledForegroundColor">#FF888888</Color>
<Color x:Key="SelectedBackgroundColor">#FFC5CBF9</Color>
<Color x:Key="SelectedUnfocusedColor">#FFDDDDDD</Color>
<Color x:Key="ControlLightColor">White</Color>
<Color x:Key="ControlMediumColor">#FF7381F9</Color>
<Color x:Key="ControlDarkColor">#FF211AA9</Color>
<Color x:Key="ControlMouseOverColor">#FF3843C4</Color>
<Color x:Key="ControlPressedColor">#FF211AA9</Color>
<Color x:Key="GlyphColor">#FF444444</Color>
<Color x:Key="GlyphMouseOver">sc#1, 0.004391443, 0.002428215, 0.242281124</Color>
<!--Border colors-->
<Color x:Key="BorderLightColor">#FFCCCCCC</Color>
<Color x:Key="BorderMediumColor">#FF888888</Color>
<Color x:Key="BorderDarkColor">#FF444444</Color>
<Color x:Key="PressedBorderLightColor">#FF888888</Color>
<Color x:Key="PressedBorderDarkColor">#FF444444</Color>
<Color x:Key="DisabledBorderLightColor">#FFAAAAAA</Color>
<Color x:Key="DisabledBorderDarkColor">#FF888888</Color>
<Color x:Key="DefaultBorderBrushDarkColor">Black</Color>
<!--Control-specific resources.-->
<Color x:Key="HeaderTopColor">#FFC5CBF9</Color>
<Color x:Key="DatagridCurrentCellBorderColor">Black</Color>
<Color x:Key="SliderTrackDarkColor">#FFC5CBF9</Color>
<Color x:Key="NavButtonFrameColor">#FF3843C4</Color>
<LinearGradientBrush x:Key="MenuPopupBrush"
EndPoint="0.5,1"
StartPoint="0.5,0">
<GradientStop Color="{DynamicResource ControlLightColor}"
Offset="0" />
<GradientStop Color="{DynamicResource ControlMediumColor}"
Offset="0.5" />
<GradientStop Color="{DynamicResource ControlLightColor}"
Offset="1" />
</LinearGradientBrush>
<LinearGradientBrush x:Key="ProgressBarIndicatorAnimatedFill"
StartPoint="0,0"
EndPoint="1,0">
<LinearGradientBrush.GradientStops>
<GradientStopCollection>
<GradientStop Color="#000000FF"
Offset="0" />
<GradientStop Color="#600000FF"
Offset="0.4" />
<GradientStop Color="#600000FF"
Offset="0.6" />
<GradientStop Color="#000000FF"
Offset="1" />
</GradientStopCollection>
</LinearGradientBrush.GradientStops>
</LinearGradientBrush>
<Style x:Key="ExpandCollapseToggleStyle"
TargetType="ToggleButton">
<Setter Property="Focusable"
Value="False" />
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="ToggleButton">
<Grid Width="15"
Height="13"
Background="Transparent">
<VisualStateManager.VisualStateGroups>
<VisualStateGroup x:Name="CheckStates">
<VisualState x:Name="Checked">
<Storyboard>
<ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.Visibility)"
Storyboard.TargetName="Collapsed">
<DiscreteObjectKeyFrame KeyTime="0"
Value="{x:Static Visibility.Hidden}" />
</ObjectAnimationUsingKeyFrames>
<ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.Visibility)"
Storyboard.TargetName="Expanded">
<DiscreteObjectKeyFrame KeyTime="0"
Value="{x:Static Visibility.Visible}" />
</ObjectAnimationUsingKeyFrames>
</Storyboard>
</VisualState>
<VisualState x:Name="Unchecked" />
<VisualState x:Name="Indeterminate" />
</VisualStateGroup>
</VisualStateManager.VisualStateGroups>
<Path x:Name="Collapsed"
HorizontalAlignment="Left"
VerticalAlignment="Center"
Margin="1,1,1,1"
Data="M 4 0 L 8 4 L 4 8 Z">
<Path.Fill>
<SolidColorBrush Color="{DynamicResource GlyphColor}" />
</Path.Fill>
</Path>
<Path x:Name="Expanded"
HorizontalAlignment="Left"
VerticalAlignment="Center"
Margin="1,1,1,1"
Data="M 0 4 L 8 4 L 4 8 Z"
Visibility="Hidden">
<Path.Fill>
<SolidColorBrush Color="{DynamicResource GlyphColor}" />
</Path.Fill>
</Path>
</Grid>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
<Style x:Key="TreeViewItemFocusVisual">
<Setter Property="Control.Template">
<Setter.Value>
<ControlTemplate>
<Border>
<Rectangle Margin="0,0,0,0"
StrokeThickness="5"
Stroke="Black"
StrokeDashArray="1 2"
Opacity="0" />
</Border>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
<Style x:Key="{x:Type TreeViewItem}"
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="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>
<VisualStateManager.VisualStateGroups>
<VisualStateGroup x:Name="SelectionStates">
<VisualState x:Name="Selected">
<Storyboard>
<ColorAnimationUsingKeyFrames Storyboard.TargetName="Bd"
Storyboard.TargetProperty="(Panel.Background).
(SolidColorBrush.Color)"
>
<EasingColorKeyFrame KeyTime="0"
Value="{StaticResource SelectedBackgroundColor}" />
</ColorAnimationUsingKeyFrames>
</Storyboard>
</VisualState>
<VisualState x:Name="Unselected" />
<VisualState x:Name="SelectedInactive">
<Storyboard>
<ColorAnimationUsingKeyFrames Storyboard.TargetName="Bd"
Storyboard.TargetProperty="(Panel.Background).
(SolidColorBrush.Color)">
<EasingColorKeyFrame KeyTime="0"
Value="{StaticResource SelectedUnfocusedColor}" />
</ColorAnimationUsingKeyFrames>
</Storyboard>
</VisualState>
</VisualStateGroup>
<VisualStateGroup x:Name="ExpansionStates">
<VisualState x:Name="Expanded">
<Storyboard>
<ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.Visibility)"
Storyboard.TargetName="ItemsHost">
<DiscreteObjectKeyFrame KeyTime="0"
Value="{x:Static Visibility.Visible}" />
</ObjectAnimationUsingKeyFrames>
</Storyboard>
</VisualState>
<VisualState x:Name="Collapsed" />
</VisualStateGroup>
</VisualStateManager.VisualStateGroups>
<ToggleButton x:Name="Expander"
Style="{StaticResource ExpandCollapseToggleStyle}"
ClickMode="Press"
IsChecked="{Binding IsExpanded,
RelativeSource={RelativeSource TemplatedParent}}"/>
<Border x:Name="Bd"
Grid.Column="1"
Background="{TemplateBinding Background}"
BorderBrush="{TemplateBinding BorderBrush}"
BorderThickness="{TemplateBinding BorderThickness}"
Padding="{TemplateBinding Padding}">
<ContentPresenter x:Name="PART_Header"
ContentSource="Header"
HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}"/>
</Border>
<ItemsPresenter x:Name="ItemsHost"
Grid.Row="1"
Grid.Column="1"
Grid.ColumnSpan="2"
Visibility="Collapsed" />
</Grid>
<ControlTemplate.Triggers>
<MultiTrigger>
<MultiTrigger.Conditions>
<Condition Property="HasHeader"
Value="false" />
<Condition Property="Width"
Value="Auto" />
</MultiTrigger.Conditions>
<Setter TargetName="PART_Header"
Property="MinWidth"
Value="75" />
</MultiTrigger>
<MultiTrigger>
<MultiTrigger.Conditions>
<Condition Property="HasHeader"
Value="false" />
<Condition Property="Height"
Value="Auto" />
</MultiTrigger.Conditions>
<Setter TargetName="PART_Header"
Property="MinHeight"
Value="19" />
</MultiTrigger>
</ControlTemplate.Triggers>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</Window.Resources>
<Grid>
<TreeView>
<TreeViewItem>
<TextBlock Text="A"/>
</TreeViewItem>
<TreeViewItem />
</TreeView>
</Grid>
</Window>