<Window.Resources>
<PathGeometry x:Key="pathUsernameRU">
<PathFigure StartPoint="0,45">
<PolyLineSegment Points="0,10"></PolyLineSegment>
</PathFigure>
</PathGeometry>
<PathGeometry x:Key="pathUsernameEN">
<PathFigure StartPoint="0,45">
<PolyLineSegment Points="0,70"></PolyLineSegment>
</PathFigure>
</PathGeometry>
<Storyboard x:Key="Storyboard">
<DoubleAnimation Storyboard.TargetName="textBlock1" Storyboard.TargetProperty="Opacity"
From="0" To="1" Duration="0:0:0.2"></DoubleAnimation>
<DoubleAnimationUsingPath Storyboard.TargetName="textBlock1" Storyboard.TargetProperty="(Canvas.Top)"
PathGeometry="{StaticResource pathUsernameEN}" Duration="0:0:0.2" Source="Y"/>
<DoubleAnimation Storyboard.TargetName="textBlock" Storyboard.TargetProperty="Opacity" From="0" To="1"
Duration="0:0:0.2" />
<DoubleAnimationUsingPath Storyboard.TargetName="textBlock" Storyboard.TargetProperty="(Canvas.Top)"
PathGeometry="{StaticResource pathUsernameRU}" Duration="0:0:0.2" Source="Y"/>
</Storyboard>
</Window.Resources>
<Grid Width="300" Height="100">
<Canvas>
<TextBox x:Name="textBox" Canvas.Top="35" Height="30" Width="300" BorderThickness="0">
<TextBox.Triggers>
<EventTrigger RoutedEvent="PreviewMouseLeftButtonDown">
<BeginStoryboard Storyboard="{StaticResource Storyboard}"/>
</EventTrigger>
</TextBox.Triggers>
</TextBox>
<Rectangle Canvas.Top="60" Fill="Black" Width="300" Height="2"></Rectangle>
<TextBlock x:Name="textBlock" Text="Username" Canvas.Top="45" Foreground="#7BBFD3" Opacity="0"/>
<TextBlock x:Name="textBlock1" Text="Имя пользователя" Canvas.Top="45" Foreground="#7BBFD3" Opacity="0"/>
</Canvas>
</Grid>
<Storyboard x:Key="Storyboard">
<DoubleAnimation Storyboard.TargetName="textBlock1" Storyboard.TargetProperty="Opacity"
To="1" Duration="0:0:0.2"/>
<DoubleAnimation Storyboard.TargetName="textBlock" Storyboard.TargetProperty="Opacity"
To="1" Duration="0:0:0.2" />
<DoubleAnimation Storyboard.TargetProperty="(Canvas.Top)"
Storyboard.TargetName="textBlock" Duration="0:0:0.2" To="70"/>
<DoubleAnimation Storyboard.TargetProperty="(Canvas.Top)"
Storyboard.TargetName="textBlock1" Duration="0:0:0.2" To="20"/>
</Storyboard>