Triggers

Property Trigger

<Window.Resources>

    <Style x:Key="Style_trigger" TargetType="Button">

        <Setter Property="Foreground" Value="Blue"/>

        <Setter Property="Content" Value="Hi!"/>

        <Style.Triggers>

            <Trigger Property="IsMouseOver" Value="True">

                <Setter Property="FontSize" Value="30"/>

                <Setter Property="Foreground" Value="Red"/>

Data Trigger 

<Window.Resources>

    <Style x:Key="WindowButt" TargetType="Button">

        <Setter Property="IsEnabled" Value="False"/>

        <Setter Property="Visibility" Value="Hidden"/>

        <Style.Triggers>

                <DataTrigger Binding="{Binding ElementName=is_bold_chbox,Path=IsChecked}" Value="True">

                <Setter Property="FontWeight" Value="Bold"/>

            </DataTrigger>

Event Trigger

<Window.Resources>    

    <Style x:Key="FocusAnimationStyle" TargetType="TextBox">

        <Setter Property="RenderTransform">

            <Setter.Value>

                <ScaleTransform ScaleX="1" ScaleY="1"/>

            </Setter.Value>

        </Setter>

        <Style.Triggers>

            <EventTrigger RoutedEvent="TextBox.GotFocus">

                <BeginStoryboard>

                    <Storyboard>

                        <DoubleAnimation

                            Storyboard.TargetProperty="(TextBox.RenderTransform).(ScaleTransform.ScaleX)"

                            To="1.1" Duration="0:0:0.2" AutoReverse="True"/>

                        <DoubleAnimation

                            Storyboard.TargetProperty="(TextBox.RenderTransform).(ScaleTransform.ScaleY)"

                            To="1.1" Duration="0:0:0.2" AutoReverse="True"/>

                    </Storyboard>

                </BeginStoryboard>

            </EventTrigger>

        </Style.Triggers>

    </Style>

</Window.Resources>

<StackPanel Margin="20">

    <!-- This TextBox uses the animation style -->

    <TextBox Style="{StaticResource FocusAnimationStyle}" Height="30" Margin="0 10"/>

    <!-- This TextBox remains unaffected -->

    <TextBox Height="30" Margin="0 10"/>

</StackPanel>

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