#172 – Changes to a Brush Cascade to Consumers of the Brush

If you create a Brush object, in XAML or code, and use that Brush in some controls, any changes to the original Brush are automatically reflected in controls that use the brush.

For example, assume that we define a teal SolidColorBrush as a resource and use it to render a Label.

    <Window.Resources>
        <SolidColorBrush x:Key="tealBrush" Color="Teal"/>
    </Window.Resources>
    <StackPanel>
        <Label Content="I'm teal!" Foreground="{StaticResource tealBrush}"/>
    </StackPanel>

Now assume that we change the brush’s color at runtime:

            SolidColorBrush theBrush = (SolidColorBrush)this.Resources["tealBrush"];
            theBrush.Color = Colors.DarkMagenta;

You’ll see that the foreground color of the Label changes immediately, as soon as we change the color of the brush.

This change notification behavior is true not only of the Brush class, but of all other classes used in rendering WPF graphics.