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How to: Paint an Area with a System Brush

  • Artikkeli

The SystemColors class provides access to system brushes and colors, such as ControlBrush, ControlBrushKey, and DesktopBrush. A system brush is a SolidColorBrush object that paints an area with the specified system color. A system brush always produces a solid fill; it can't be used to create a gradient.

You can use system brushes as either a static or a dynamic resource. Use a dynamic resource if you want the brush to update automatically if the user changes the system brush as the application is running; otherwise, use a static resource. The SystemColors class contains a variety of static properties that follow a strict naming convention:

  • *<SystemColor>*Brush

    Gets a static reference to a SolidColorBrush of the specified system color.

  • *<SystemColor>*BrushKey

    Gets a dynamic reference to a SolidColorBrush of the specified system color.

  • *<SystemColor>*Color

    Gets a static reference to a Color structure of the specified system color.

  • *<SystemColor>*ColorKey

    Gets a dynamic reference to the Color structure of the specified system color.

A system color is a Color structure that can be used to configure a brush. For example, you can create a gradient using system colors by setting the Color properties of a LinearGradientBrush object's gradient stops with system colors. For an example, see Use System Colors in a Gradient.

Example

The following example uses a dynamic system brush reference to set the Background of a button.

<Page xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
  xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
  WindowTitle="SystemColors Example" Background="White">  
  <StackPanel Margin="20">
 
    <!-- Uses a dynamic resource to set the 
         background of a button. 
         If the desktop brush changes while this application
         is running, this button will be updated. -->
    <Button 
      Background="{DynamicResource {x:Static SystemColors.DesktopBrushKey}}" 
      Content="Hello, World!" />

  </StackPanel>
</Page>

The next example uses a static system brush reference to set the Background of a button.

<Page xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
  xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
  WindowTitle="SystemColors Example" Background="White">  
  <StackPanel Margin="20">
 
    <!-- Uses a static brush to set the
         background of a button. 
         If the desktop brush changes while this application
         is running, this button will not be updated until
         the page is loaded again. -->
    <Button 
      Background="{x:Static SystemColors.DesktopBrush}" 
      Content="Hello, World!"  /> 

  </StackPanel>
</Page>

For an example showing how to use a system color in a gradient, see Use System Colors in a Gradient.

See also