Trigger Property=FrameworkElement.IsFocused

image_pdfimage_print


   
     

<Page xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
      xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
      HorizontalAlignment="Stretch" VerticalAlignment="Stretch">
    <Page.Resources>
        <Style x:Key="widthOnFocus">
          <Style.Triggers>
            <Trigger Property="FrameworkElement.IsFocused" Value="True">
              <Trigger.EnterActions>
                <BeginStoryboard Name="changeWidth">
                  <Storyboard>
                    <DoubleAnimation Storyboard.TargetProperty="(FrameworkElement.Width)" To="300" Duration="0:0:5" />
                  </Storyboard>
                </BeginStoryboard>
              </Trigger.EnterActions>
              <Trigger.ExitActions>
                <RemoveStoryboard BeginStoryboardName="changeWidth" />
              </Trigger.ExitActions>
            </Trigger>
          </Style.Triggers>
        </Style>
    </Page.Resources>
    
    <StackPanel>
      <TextBox Style="{StaticResource widthOnFocus}" Width="200" />
    </StackPanel>


</Page>