Professional Visual Basic 2012 and .NET 4.5 Programming

Styles

Developers of business applications might be a bit wary of becoming an expert in styling. Windows Forms had no such capability, and web applications often have specialists that do the styling.

However, styles in XAML are quite a bit more flexible than styles in earlier technologies, and address functionality that's not strictly cosmetic. That means developers need to understand styles, too.

What Is a Style?

At the most basic level, a Style in XAML is simply a way to set several property values for an element at one time. In syntactical terms, a Style is a collection of Setter objects, and each Setter object knows how to set a particular property to a particular value.

Here is a simple Style for a Button element (code file: SimpleStyle.xaml):

<Style x:Key="ButtonStyle" TargetType="Button">
    <Setter Property="Margin" Value="4" />
    <Setter Property="FontSize" Value="22"/>
    <Setter Property="FontStyle" Value="Italic" />
    <Setter Property="Foreground" >
        <Setter.Value>
            <LinearGradientBrush
                EndPoint="0.8,0.8" 
                StartPoint="0.2,0.2">
                <GradientStop Color="DarkBlue" Offset="0"/>
                <GradientStop Color="ForestGreen" Offset="1"/>
            </LinearGradientBrush>
        </Setter.Value>
    </Setter>
</Style>

In this case, the Style is declared as a resource, and so has an x:Key attribute. That's the common case. There are a few scenarios where a Style is not used as a resource, and in fact you will see one a bit further on. However, normally the power of a Style is to apply it widely through much or all of an application, ...