将玻璃框扩展到 WPF 应用程序中

本主题演示如何将 Windows Vista 玻璃框扩展到 Windows Presentation Foundation (WPF) 应用程序的工作区。

地址栏中的扩展玻璃框

下图显示扩展到 Internet Explorer 7 地址栏中的玻璃框：

若要在 WPF 应用程序上扩展玻璃框，需要访问非托管 API。 以下代码示例针对将框扩展到工作区所需的两个 API 执行平台调用 (pinvoke)。 其中每一个 API 都在名为 NonClientRegionAPI 的类中声明。

[StructLayout(LayoutKind.Sequential)]
public struct MARGINS
{
    public int cxLeftWidth;      // width of left border that retains its size
    public int cxRightWidth;     // width of right border that retains its size
    public int cyTopHeight;      // height of top border that retains its size
    public int cyBottomHeight;   // height of bottom border that retains its size
};

[DllImport("DwmApi.dll")]
public static extern int DwmExtendFrameIntoClientArea(
    IntPtr hwnd,
    ref MARGINS pMarInset);

<StructLayout(LayoutKind.Sequential)>
Public Structure MARGINS
    Public cxLeftWidth As Integer ' width of left border that retains its size
    Public cxRightWidth As Integer ' width of right border that retains its size
    Public cyTopHeight As Integer ' height of top border that retains its size
    Public cyBottomHeight As Integer ' height of bottom border that retains its size
End Structure

<DllImport("DwmApi.dll")>
Public Shared Function DwmExtendFrameIntoClientArea(ByVal hwnd As IntPtr, ByRef pMarInset As MARGINS) As Integer
End Function

DwmExtendFrameIntoClientArea 是将框扩展到工作区的 DWM 函数。 它采用两个参数：一个窗口句柄和一个 MARGINS 结构。 MARGINS 用于告知 DWM 应向工作区扩展多少额外框。

已加载事件上的扩展玻璃框

若要使用 DwmExtendFrameIntoClientArea 函数，必须获取窗口句柄。 在 WPF 中，可以从 HwndSource 的 Handle 属性获取窗口句柄。 在以下示例中，框在窗口的 Loaded 事件中扩展到客户区。

void OnLoaded(object sender, RoutedEventArgs e)
{
   try
   {
      // Obtain the window handle for WPF application
      IntPtr mainWindowPtr = new WindowInteropHelper(this).Handle;
      HwndSource mainWindowSrc = HwndSource.FromHwnd(mainWindowPtr);
      mainWindowSrc.CompositionTarget.BackgroundColor = Color.FromArgb(0, 0, 0, 0);

      // Get System Dpi
      System.Drawing.Graphics desktop = System.Drawing.Graphics.FromHwnd(mainWindowPtr);
      float DesktopDpiX = desktop.DpiX;
      float DesktopDpiY = desktop.DpiY;

      // Set Margins
      NonClientRegionAPI.MARGINS margins = new NonClientRegionAPI.MARGINS();

      // Extend glass frame into client area
      // Note that the default desktop Dpi is 96dpi. The  margins are
      // adjusted for the system Dpi.
      margins.cxLeftWidth = Convert.ToInt32(5 * (DesktopDpiX / 96));
      margins.cxRightWidth = Convert.ToInt32(5 * (DesktopDpiX / 96));
      margins.cyTopHeight = Convert.ToInt32(((int)topBar.ActualHeight + 5) * (DesktopDpiX / 96));
      margins.cyBottomHeight = Convert.ToInt32(5 * (DesktopDpiX / 96));

      int hr = NonClientRegionAPI.DwmExtendFrameIntoClientArea(mainWindowSrc.Handle, ref margins);
      //
      if (hr < 0)
      {
         //DwmExtendFrameIntoClientArea Failed
      }
   }
   // If not Vista, paint background white.
   catch (DllNotFoundException)
   {
      Application.Current.MainWindow.Background = Brushes.White;
   }
}

工作区中的扩展玻璃框

以下示例演示一个简单的窗口，在该窗口中框扩展到工作区。 框扩展到包含两个 TextBox 对象的上边框的后面。

<Window x:Class="SDKSample.Window1"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="Extended Glass in WPF" Height="300" Width="400"
    Loaded="OnLoaded" Background="Transparent"
    >
  <Grid ShowGridLines="True">
    <DockPanel Name="mainDock">
      <!-- The border is used to compute the rendered height with margins.
           topBar contents will be displayed on the extended glass frame.-->
      <Border Name="topBar" DockPanel.Dock="Top" >
        <Grid Name="grid">
          <Grid.ColumnDefinitions>
            <ColumnDefinition MinWidth="100" Width="*"/>
            <ColumnDefinition Width="Auto"/>
          </Grid.ColumnDefinitions>
          <TextBox Grid.Column="0" MinWidth="100" Margin="0,0,10,5">Path</TextBox>
          <TextBox Grid.Column="1" MinWidth="75" Margin="0,0,0,5">Search</TextBox>
        </Grid>
      </Border>
      <Grid DockPanel.Dock="Top" >
        <Grid.ColumnDefinitions>
          <ColumnDefinition/>
        </Grid.ColumnDefinitions>
        <TextBox Grid.Column="0" AcceptsReturn="True"/>
      </Grid>
    </DockPanel>
  </Grid>
</Window>

下图演示扩展到 WPF 应用程序的玻璃框：

另请参阅

• 桌面窗口管理器概述
• 桌面窗口管理器模糊概述
• DwmExtendFrameIntoClientArea