ControlTemplate Trigger - xaml

Question

<Style TargetType="{x:Type TextBox}">
<Setter Property="SnapsToDevicePixels" Value="True" />
<Setter Property="OverridesDefaultStyle" Value="True" />
<Setter Property="KeyboardNavigation.TabNavigation" Value="None" />
<Setter Property="FocusVisualStyle" Value="{x:Null}" />
<Setter Property="MinWidth" Value="120" />
<Setter Property="MinHeight" Value="25" />
<Setter Property="AllowDrop" Value="true" />
<Setter Property="FontSize" Value="16"/>
<Setter Property="FontFamily" Value="Arial"/>
<Setter Property="VerticalContentAlignment" Value="Center"/>
<Setter Property="VerticalAlignment" Value="Bottom"/>
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type TextBoxBase}">
<Border Name="Border" CornerRadius="6" Padding="2" BorderBrush="Black" BorderThickness="2,1">
<ScrollViewer Margin="0" x:Name="PART_ContentHost" />
</Border>
<ControlTemplate.Triggers>
</ControlTemplate.Triggers>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
The code above is currently what I have for my text box. What do I put in the ControlTemplate.Trigger in order for my border to change from its color black to Blue or increase the Border size when it is clicked on. I have tried a few things without any luck. This includes style.Triggers and events. Please post the code that goes between the ControlTemplate.Trigger.

Answer 1

This assumes you want to border to be changed when you have it focused, since clicking a textbox focuses it. There is no OnClick property available, this changes the border of a textbox once you have it focused.
<Trigger Property="IsKeyboardFocusWithin"
Value="True">
<Setter Property="BorderBrush"
TargetName="Border"
Value="Blue"/>
</Trigger>
Edit:
To simply remove focus, add the following MouseDown event handler to your Window or Page:
MouseDown="Window_MouseDown"
And in your code behind:
private void Window_MouseDown(object sender, MouseButtonEventArgs e)
{
Keyboard.ClearFocus();
}
This will correctly remove focus from your TextBox and thus unset the trigger to have a black bar again.