Consolidating common WPF Styles

Question

I have various Style elements in my WPF XAML that are the same except for the data binding property, e.g.:

<Style x:Key="HasAlphaStyle" TargetType="TextBlock">
    <Style.Triggers>
        <DataTrigger Binding="{Binding Path=HasAlpha, UpdateSourceTrigger=PropertyChanged}" Value="True">
            <Setter Property="Background" Value="Red"/>
            <Setter Property="Foreground" Value="White"/>
            <Setter Property="FontWeight" Value="Bold"/>                   
        </DataTrigger>
        <DataTrigger Binding="{Binding Path=HasAlpha, UpdateSourceTrigger=PropertyChanged}" Value="False">
            <Setter Property="Background" Value="LightGreen"/>
            <Setter Property="Foreground" Value="Black"/>
            <Setter Property="FontWeight" Value="Normal"/>
        </DataTrigger>
    </Style.Triggers>
</Style>

<Style x:Key="HasBetaStyle" TargetType="TextBlock">
    <Style.Triggers>
        <DataTrigger Binding="{Binding Path=HasBeta, UpdateSourceTrigger=PropertyChanged}" Value="True">
            <Setter Property="Background" Value="Red"/>
            <Setter Property="Foreground" Value="White"/>
            <Setter Property="FontWeight" Value="Bold"/>                   
        </DataTrigger>
        <DataTrigger Binding="{Binding Path=HasBeta, UpdateSourceTrigger=PropertyChanged}" Value="False">
            <Setter Property="Background" Value="LightGreen"/>
            <Setter Property="Foreground" Value="Black"/>
            <Setter Property="FontWeight" Value="Normal"/>
        </DataTrigger>
    </Style.Triggers>
</Style>

The style is applied to a control like:

<TextBlock Style="{StaticResource HasAlphaStyle}" .../>

Is there a way I can consolidate my HasAlphaStyle and HasBetaStyle so that the property setters don't have to be duplicated? The only difference between the two is the Binding Path to the property.

Answer 1

I would create an attached property and have my triggers on that instead of having data triggers. Sample code as below:

Attached Property

public static class TextBlockBehavior
{
        public static readonly DependencyProperty HasValueProperty = 
            DependencyProperty.RegisterAttached("HasValue", typeof(bool), typeof(TextBlockBehavior),
            new FrameworkPropertyMetadata(true, FrameworkPropertyMetadataOptions.None));

        public static void SetHasValue(DependencyObject depObject, bool value)
        {
            depObject.SetValue(HasValueProperty, value);
        }

        public static bool GetHasValue(DependencyObject depObject)
        {
            return (bool)depObject.GetValue(HasValueProperty);
        }
}

and then your combined style would become

<Style x:Key="HasValueStyle" TargetType="TextBlock">
    <Style.Triggers>
        <Trigger Property="behaviors:TextBlockBehavior.HasValue" Value="True">
            <Setter Property="Background" Value="Red"/>
            <Setter Property="Foreground" Value="White"/>
            <Setter Property="FontWeight" Value="Bold"/>                   
        </Trigger>
        <Trigger Property="behaviors:TextBlockBehavior.HasValue" Value="False">
            <Setter Property="Background" Value="LightGreen"/>
            <Setter Property="Foreground" Value="Black"/>
            <Setter Property="FontWeight" Value="Normal"/>
        </Trigger>
    </Style.Triggers>
</Style>

and you can write your textblocks as

<TextBlock Style="{StaticResource HasValueStyle}"
           behaviors:TextBlockBehavior.HasValue="{Binding Path=HasAlpha, UpdateSourceTrigger=PropertyChanged}"            .../>

<TextBlock Style="{StaticResource HasValueStyle}"
           behaviors:TextBlockBehavior.HasValue="{Binding Path=HasBeta, UpdateSourceTrigger=PropertyChanged}"            .../>