Trigger
A trigger is used to performs actions and to
perform action applies property value of the trigger.
Properties
Setter - This property describes the
values to apply when the specified condition has been met.
Value - This property represents the
value to be compared with the property value of the control (element).
SourceName - This property represents
the name of the object with the property that causes the associated setters to
be applied.
Property - This property returns the
value that is used to compared with the Value property of the trigger.
For example
Creating one TextBox and one Button
control on the window form.
XAML code
<TextBox
Height="23"
HorizontalAlignment="Left"
Margin="69,62,0,0"
Name="TextBox1"
VerticalAlignment="Top"
Width="120"
/>
<Button
Content="Button"
Height="23"
HorizontalAlignment="Left"
Margin="91,122,0,0"
Name="Button1"
VerticalAlignment="Top"
Width="75"
/>
</Grid>
The form looks like this.
Figure1.gif
Now using IsMousedOver and IsFocused
action on the TextBox and Button control.
Using
Trigger for the
TextBox
<Style
TargetType="{x:Type
TextBox
}">
<Style.Triggers>
<Trigger
Property="IsMouseOver"
Value="False">
<Setter
Property="Background"
Value="red"
/>
</Trigger>
<Trigger
Property="IsFocused"
Value="True">
<Setter
Property="Background"
Value="Red"
/>
</Trigger>
</Style.Triggers>
</Style>
Using trigger for Button Control.
<Style
TargetType="{x:Type
Button}">
<Style.Triggers>
<Trigger
Property="IsMouseOver"
Value="
True">
<Setter
Property="FontWeight"
Value="Bold"/>
<Setter
Property="Foreground"
Value="Red"/>
<Setter
Property="Background"
Value="
Green"/>
</Trigger>
</Style.Triggers>
</Style>
The above code defines that for the TextBox
the Trigger property is set to false.
<Trigger
Property="IsMouseOver"
Value="False">
For the Button the Trigger property is set
to true.
<Trigger
Property="IsMouseOver"
Value="False">
XAML code
<Window
x:Class="MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="MainWindow"
Height="350"
Width="525">
<Window.Resources>
<Style
TargetType="{x:Type
TextBox
}">
<Style.Triggers>
<Trigger
Property="IsMouseOver"
Value="False">
<Setter
Property="Background"
Value="red"
/>
</Trigger>
<Trigger
Property="IsFocused"
Value="True">
<Setter
Property="Background"
Value="Red"
/>
</Trigger>
</Style.Triggers>
</Style>
<Style
TargetType="{x:Type
Button}">
<Style.Triggers>
<Trigger
Property="IsMouseOver"
Value="
True">
<Setter
Property="FontWeight"
Value="Bold"/>
<Setter
Property="Foreground"
Value="Red"/>
<Setter
Property="Background"
Value="
Green"/>
</Trigger>
</Style.Triggers>
</Style>
</Window.Resources>
<Grid>
<TextBox
Height="64"
HorizontalAlignment="Left"
Margin="128,84,0,0"
Name="TextBox1"
VerticalAlignment="Top"
Width="159"
/>
<Button
Content="Button"
Height="33"
HorizontalAlignment="Left"
Margin="107,184,0,0"
Name="Button1"
VerticalAlignment="Top"
Width="218"
/>
</Grid>
</Window>
Now run the application and move the mouse over
the TextBox and Button control.
Figure2.gif