WPF TreeViewItem展開式動畫

Question

我使用了問題Wpf treeview - i want to animate the expansion of the nodes中的代碼，但動畫在第一次展開時不起作用，它對於後續的展開事件起作用。

有什麼想法？

Answer 1

改變觸發值設置爲false 和交換EnterAction的故事板ExitAction的

Answer 2

這裏是一個解決方案：

 <Style x:Key="TreeViewItemStyle1" TargetType="{x:Type TreeViewItem}"> 
     <Setter Property="Background" Value="Transparent"/> 
        <Setter Property="BorderBrush" Value="Transparent"/> 
        <Setter Property="FontFamily" Value="Verdana"/> 
        <Setter Property="FontSize" Value="12"/> 
        <Setter Property="FontWeight" Value="light"/> 
        <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"/> 
        <Setter Property="Margin" Value="1"/> 
        <Setter Property="Foreground" Value="{DynamicResource grau80}"/> 
        <Setter Property="IsExpanded" Value="{Binding IsExpanded, Mode=TwoWay}" /> 
        <Setter Property="IsSelected" Value="{Binding IsSelected, Mode=TwoWay}" /> 
        <Setter Property="Template"> 
        <Setter.Value> 
         <ControlTemplate TargetType="{x:Type TreeViewItem}"> 
         <ControlTemplate.Resources> 
         <Storyboard x:Key="Timeline1"> 
          <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.Visibility)" Storyboard.TargetName="ItemsHost"> 
           <DiscreteObjectKeyFrame KeyTime="0" Value="{x:Static Visibility.Collapsed}"/> 
           <DiscreteObjectKeyFrame KeyTime="0:0:0.1" Value="{x:Static Visibility.Visible}"/> 
          </ObjectAnimationUsingKeyFrames> 
          <DoubleAnimation Storyboard.TargetName="ItemsHost" Storyboard.TargetProperty="LayoutTransform.ScaleY" To="1" Duration="0:0:0.4"> 
          <DoubleAnimation.EasingFunction> 
           <CircleEase EasingMode="EaseInOut"/> 
          </DoubleAnimation.EasingFunction> 
          </DoubleAnimation> 
          <DoubleAnimation Storyboard.TargetName="ItemsHost" Storyboard.TargetProperty="Opacity" To="1" Duration="0:0:0.5"/> 
         </Storyboard> 
         <Storyboard x:Key="Timeline2"> 
          <DoubleAnimation Storyboard.TargetName="ItemsHost" Storyboard.TargetProperty="LayoutTransform.ScaleY" To="0" Duration="0:0:0.3"> 
          <DoubleAnimation.EasingFunction> 
           <CircleEase EasingMode="EaseInOut"/> 
          </DoubleAnimation.EasingFunction> 
          </DoubleAnimation> 
          <DoubleAnimation Storyboard.TargetName="ItemsHost" Storyboard.TargetProperty="Opacity" To="0" Duration="0:0:0.4" /> 
          <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.Visibility)" Storyboard.TargetName="ItemsHost"> 
           <DiscreteObjectKeyFrame KeyTime="0:0:0.4" Value="{x:Static Visibility.Visible}"/> 
           <DiscreteObjectKeyFrame KeyTime="0:0:0.5" Value="{x:Static Visibility.Collapsed}"/> 
          </ObjectAnimationUsingKeyFrames> 
         </Storyboard> 
         </ControlTemplate.Resources> 
         <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" Style="{DynamicResource TB_Tree}" IsChecked="{Binding Path=IsExpanded, RelativeSource={RelativeSource TemplatedParent}}" ClickMode="Press"/> 
          <Border Name="Bd" Grid.Column="1" CornerRadius="2" Background="{TemplateBinding Background}" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="0.8" Padding="{TemplateBinding Padding}"> 
          <ContentPresenter x:Name="PART_Header" ContentSource="Header" HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" Margin="2,0"/> 
          </Border> 
           <ItemsPresenter x:Name="ItemsHost" Grid.Row="1" Grid.Column="1" Grid.ColumnSpan="2" Visibility="Collapsed" Opacity="0"> 
           <ItemsPresenter.LayoutTransform> 
            <ScaleTransform ScaleY="0" /> 
           </ItemsPresenter.LayoutTransform> 
           </ItemsPresenter> 
         </Grid> 
         <ControlTemplate.Triggers> 
          <Trigger Property="IsExpanded" Value="true"> 
           <Trigger.EnterActions> 
            <BeginStoryboard Storyboard="{StaticResource Timeline1}"/> 
           </Trigger.EnterActions> 
           <Trigger.ExitActions> 
            <BeginStoryboard Storyboard="{StaticResource Timeline2}"/> 
           </Trigger.ExitActions> 
          </Trigger> 
          <Trigger Property="HasItems" Value="false"> 
           <Setter TargetName="Expander" Property="Visibility" Value="Hidden"/> 
          </Trigger> 
          <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> 
          <Trigger Property="IsSelected" Value="true"> 
           <Setter TargetName="Bd" Property="Background" Value="{DynamicResource Orange}"/> 
           <Setter Property="Foreground" Value="{DynamicResource weiss}"/> 
          </Trigger> 
          <MultiTrigger> 
           <MultiTrigger.Conditions> 
            <Condition Property="IsSelected" Value="true"/> 
            <Condition Property="IsSelectionActive" Value="false"/> 
           </MultiTrigger.Conditions> 
           <Setter TargetName="Bd" Property="BorderBrush" Value="{DynamicResource Orange}"/> 
           <Setter TargetName="Bd" Property="Background" Value="{DynamicResource weiss}"/> 
           <Setter Property="Foreground" Value="{DynamicResource grau60}"/> 
          </MultiTrigger> 
          <Trigger Property="IsEnabled" Value="false"> 
           <Setter Property="Foreground" Value="{DynamicResource weiss}"/> 
          </Trigger> 
         </ControlTemplate.Triggers> 
         </ControlTemplate> 
        </Setter.Value> 
        </Setter>