WPF Styles and Triggers - WPF controls (2023)

In this article, I'll introduce you to the concepts of WPF styles and triggers.

WPF styles consist of setters and triggers that are supposed to change the style and behavior of a control. Technically, the purpose of a style is to set a dependency property on a control.

Some style use cases:

• Change the color of the control
• Change the audit template of an audit
• add animations
• add behavior
• define topics

Define WPF styles

In its simplest form, a WPF style simply consists of one or more Setters.

<resource window> <style target type="text block"> <positive property="perspective" value="blue"/> style>resource window>
Codetaal: HTML, XML (xml)

In the list above, you can see a style that targets "TextBlock" and includes a setter for the "Foreground" property. When this style is applied to a TextBlock, the Foreground property is set to "Blue".

<window X: great="StylesTutorial.MainWindow" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmln:d="http://schemas.microsoft.com/expression/blend/2008" xmlns: mc="http://schemas.openxmlformats.org/markup-compatibility/2006" xmlns:local="clr-naamruimte:StylesTutorial" mc: can be ignored="Hoi" title="Main Window" high=“350” width="525"> <resource window> <style target type="text block"> <positive property="perspective" value="blue"/> style>resource window><rooster> <text block text="Hello World!"/> rooster>window>
Codetaal: HTML, XML (xml)

You can override the Foreground property when you declare the Foreground value locally where you declare the TextBlock element. Look at meItem dependency propertiesMore about the value assessment series.

<window X: great="StylesTutorial.MainWindow" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmln:d="http://schemas.microsoft.com/expression/blend/2008" xmlns: mc="http://schemas.openxmlformats.org/markup-compatibility/2006" xmlns:local="clr-naamruimte:StylesTutorial" mc: can be ignored="Hoi" title="Main Window" high=“350” width="525"> <resource window> <style target type="text block"> <positive property="perspective" value="blue"/> style>resource window><rooster> <text block text="Hello World!" perspective="Black"/> rooster>window>
Codetaal: HTML, XML (xml)

In the list above, the TextBlock style is applied to the TextBlock elements in the grid. However, the local value "Black" overrides the Style Setter because it has a higher priority in the evaluation order.

Styles can be declared in different places and can have different scopes.

Native WPF Styles

You can declare styles directly where they are used.

<text block text="Hello World!"> <TextBlock.Style> <style target type="text block"> <positive property="perspective" value="blue"/> style>TextBlock.Style>text block>
Codetaal: HTML, XML (xml)

If you define a style here, it can only be applied to this TextBlock element. It cannot be applied to other TextBlock elements. I rarely use this method.

Indirect WPF Styles

You may have noticed the "TargetType" attribute in the style declaration. Using TargetType has two effects:

• Sets the full style target type scope to "TextBlock". This means you can just write "Foreground" instead of "TextBlock.Foreground". If TargetType is omitted, the property name must always be preceded by the class type.
• Automatically applies your style to all TextBlock instances within the scope of the style.

Tip: Our style only applies if it is included in the source dictionary of the XAML file. This can happen if the style is declared directly in the source section of the XAML file. If it is declared in another resource dictionary, it must be included in the XAML file where we want to use this style.

(Video) C# WPF Tutorial #21 - Styles and ControlTemplates

Clear WPF Styles

If you don't want your style to apply to all elements of a certain type, you must define a key for the style. If a style has a key name, you must reference your style in the target element. It is no longer applied automatically!

<window X: great="StylesTutorial.MainWindow" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmln:d="http://schemas.microsoft.com/expression/blend/2008" xmlns: mc="http://schemas.openxmlformats.org/markup-compatibility/2006" xmlns:local="clr-naamruimte:StylesTutorial" mc: can be ignored="Hoi" title="Main Window" high=“350” width="525"> <resource window> <style x: key="Text Block Style" target type="text block"> <positive property="perspective" value="blue"/> style>resource window><rooster> <text block text="Hello World!" style="{StaticResource TextBlockStyle}"/> rooster>window>
Codetaal: HTML, XML (xml)

In the list above, we've given our style a unique name using the "TextBlockStyle" key. To apply the style, we need to reference it in the TextBlock element.

WPF template style checker

Styles are often used within control templates and are used to apply control templates to controls.

The list below shows the control template styles automatically generated by Visual Studio. I seeCheck template articlesLearn more about making it.

<style x: key="Visiefocus"> <positive property="control.template"> <specified value> <control pattern> <rectangle gain="2" SnapsToDevicePixels="Real" Heart attack="{DynamicResource {x:Static SystemColors.ControlTextBrushKey}}" stroke thickness="1" StrokeDashArray=“1 2”/> control pattern> specified value>positive>style><monochrome brush x: key="button.static.background" colour="#FFDDDDDD"/><monochrome brush x: key="static.boundary button" colour="#FF707070"/><monochrome brush x: key="Button.MouseOver.Background" colour="#FFBEE6FD"/><monochrome brush x: key="Button.MouseOver.Border" colour="#FF3C7FB1"/><monochrome brush x: key="button.pressed.background" colour="#FFC4E5F6"/><monochrome brush x: key="button.pressed.border" colour="#FF2C628B"/><monochrome brush x: key="button.disabled.background" colour="#FFF4F4F4"/><monochrome brush x: key="button.disabled.border" colour="#FFADB2B5"/><monochrome brush x: key="button.disabled.foreground" colour="#FF838383"/><style x: key="Button Style" target type="{x:typeknop}"> <positive property="Visual Style Focus" value="{StaticResource FocusVisual}"/> <positive property="Dossier" value="{StaticResource-knop.Static.Background}"/> <positive property="Wrist brush" value="{StaticResource-knop.Static.Border}"/> <positive property="perspective" value="{DynamicResource {x:Static SystemColors.ControlTextBrushKey}}"/> <positive property="boundary thickness" value="1"/> <positive property="Horizontal Content Alignment" value="center"/> <positive property="Vertical Content Alignment" value="center"/> <positive property="filling" value="1"/> <positive property="role model"> <specified value> <control pattern target type="{x:typeknop}"> <Limitation x: name="Boundary" contourborstel="{TemplateBinding BorderBrush}" edge thickness="{TemplateBinding BorderThickness}" Dossier="{TemplateBinding Background}" SnapsToDevicePixels="Real"> <content presenter x: name="Content Presenter" Focus="Inaccurate" Horizontal alignment="{TemplateBinding Horizo​​ntalContentAlignment}" gain="{TemplateBinding Fill}" Determine the access keys="Real" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" vertical alignment="{TemplateBinding VerticalContentAlignment}"/> Limitation> <ControlTemplate.Trigger> <trekker property="Standard" value="Real"> <positive property="Wrist brush" target name="Boundary" value="{DynamicResource {x:Static SystemColors.HighlightBrushKey}}"/> trekker><trekker property="Yes the Mouse" value="Real"> <positive property="Dossier" target name="Boundary" value="{StaticResource-knop.MouseOver.Background}"/> <positive property="Wrist brush" target name="Boundary" value="{StaticResource-knop.MouseOver.Border}"/> trekker><trekker property="type" value="Real"> <positive property="Dossier" target name="Boundary" value="{StaticResourceButton.Pressed.Background}"/> <positive property="Wrist brush" target name="Boundary" value="{StaticResource Button.Pressed.Border}"/> trekker><trekker property="allow" value="Inaccurate"> <positive property="Dossier" target name="Boundary" value="{StaticResource Button.Disabled.Background}"/> <positive property="Wrist brush" target name="Boundary" value="{StaticResourceButton.Disabled.Border}"/> <positive property="TextElement.Foreground" target name="Content Presenter" value="{StaticResource Button.Disabled.Foreground}"/> trekker>ControlTemplate.Trigger>control pattern>specified value>positive>style>
Codetaal: HTML, XML (xml)

Styles can be applied simply by referencing their key names.

<knob style="{DynamicResource ButtonStyle}"/>
(Video) Triggers in WPF
Codetaal: HTML, XML (xml)

WPF style inheritance

WPF styles can inherit from each other. This is useful if you have some styles that need to be applied to all controls of different base classes.

To base your style on another style, you must use the "BasedOn" attribute in the style declaration to reference the other style.

<window X: great="StylesTutorial.MainWindow" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmln:d="http://schemas.microsoft.com/expression/blend/2008" xmlns: mc="http://schemas.openxmlformats.org/markup-compatibility/2006" xmlns:local="clr-naamruimte:StylesTutorial" mc: can be ignored="Hoi" title="Main Window" high=“350” width="525"> <resource window> <style target type="frame-element" x: key="frame-elementstijl"> <positive property="gain" value=“10”/> style><style target type="text block" based on="{StaticResource FrameworkElementStyle}"> <positive property="perspective" value="blue"/> style><style target type="knob" based on="{StaticResource FrameworkElementStyle}"> <positive property="perspective" value="blue"/> style>resource window><stack table> <text block text="Hello World!"/> <knob contents="Hello World!"/> stack table>window>
Codetaal: HTML, XML (xml)

In the list above, I declare a style that targets "FrameworkElement" and set the margin to 10. This style is inherited by Button and TextBlock. Because the Button and TextBlock styles do not have a key, they are automatically applied to the TextBlock and button in the StackPanel.

So far we have used setters to set properties. However, WPF styles are much more powerful. You can set properties based on rules.

In WPF, there are different types of triggers, which are described in the following sections.

function activation

The most common type of trigger is a property trigger rule. Property tag rules can define properties based on the value of another property.

<window X: great="StylesTutorial.MainWindow" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmln:d="http://schemas.microsoft.com/expression/blend/2008" xmlns: mc="http://schemas.openxmlformats.org/markup-compatibility/2006" xmlns:local="clr-naamruimte:StylesTutorial" mc: can be ignored="Hoi" title="Main Window" high=“350” width="525"> <resource window> <style target type="text block"> <styles.triggers> <trekker property="Yes the Mouse" value="Real"> <positive property="perspective" value="vegetables"/> <positive property="Dossier" value="yellow"/> trekker> styles.triggers><positive property="perspective" value="blue"/> <positive property="Dossier" value="Light brown"/> style>resource window><stack table> <text block text="Hello World!"/> stack table>window>
(Video) WPF Triggers Part 1: Property & DataTrigger
Codetaal: HTML, XML (xml)

In the list above, we have a style with a setter that sets the Foreground property to "Blue" and the Background property to "Beige". In addition, we have a property tag rule that is applied when the TextBlock.IsMouseOver property is true. The Property Trigger contains two setters for the foreground and background properties.

When the user hovers over the text block, the foreground color changes to "green" and the background color to "yellow".

But what happens if the IsMouseOver property is changed to false? Don't we need another property trigger for the IsMouseOver=false case?

To answer this question, we need to thinkDependency Properties Evaluation Series.Triggers have a higher priority than regulators. This is why the foreground changes from blue to green when the Property Trigger is activated. If the Property Trigger becomes inactive, WPF will reevaluate the priority order and look for another source of value. In our case it is a Setter of the same style. So it turns blue again. The background color also changes to beige.

event trigger

Compared to Property Trigger, there are two differences:

• Event triggers respond to events, not property changes
• Event trigger rules cannot contain setters to set properties, but perform other actions, such as storyboarding

In the example below, we add animation to the Opacity property of a TextBlock. When the user hovers over the text block, we change the opacity to 0.5 for 1 second. When the user exits the TextBlock, we change the opacity to 1.

<style target type="text block"> <styles.triggers> <event trigger routed event="mouse input"> <EventTrigger.Actions> <launch the storyboard> <Storyboard> <Duplicate animation using keyframes storyboard.TargetProperty="Cover" period="0:0:1"> <LineairDoubleKeyFrame value=“0,5” critical moment="0:0:2"/> Duplicate animation using keyframes> Storyboard>launch the storyboard>EventTrigger.Actions>event trigger><event trigger routed event="go away mouse"> <EventTrigger.Actions> <launch the storyboard> <Storyboard> <Duplicate animation using keyframes storyboard.TargetProperty="Cover" period="0:0:1"> <LineairDoubleKeyFrame value="1" critical moment="0:0:2"/> Duplicate animation using keyframes>Storyboard>launch the storyboard>EventTrigger.Actions>event trigger>styles.triggers>style>
Codetaal: HTML, XML (xml)

data activation

Last but not least are data triggers. Data triggers are very similar to property trigger rules. The only difference is that you can use data binding to connect to another component or data environment. However, you can use property setters just like property triggers.

<window X: great="StylesTutorial.MainWindow" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmln:d="http://schemas.microsoft.com/expression/blend/2008" xmlns: mc="http://schemas.openxmlformats.org/markup-compatibility/2006" xmlns:local="clr-naamruimte:StylesTutorial" mc: can be ignored="Hoi" title="Main Window" high=“350” width="525"> <resource window> resource window><stack table> <switch box x: name="finch"/> <text block text="Hello World!"> <TextBlock.Style> <style target type="text block"> <styles.triggers> <data activation tie up="{Binding ElementName=checkbox, Path=IsChecked}" value="Real"> <positive property="perspective" value="blue"/> data activation> styles.triggers>style>TextBlock.Style>text block>stack table>window>
Codetaal: HTML, XML (xml)