做這個工作列界面縮略圖時，使用VisualBrush将子界面的實時圖像填充到Rectangle
1 Rectangle emptyRectangle = new Rectangle
2 {
3 Width = 250D,
4 Height = 130D,
5 Fill = new VisualBrush { Visual = child },
6 Margin = new Thickness(2)
7 };
又分别使用了兩個Border來模彷Windows7工作列縮略圖的圓角
使用圓角
//給工作列的Popup界面縮略圖應用圓角
Border visualBorder = new Border
{
BorderBrush = Brushes.Transparent,
BorderThickness = new Thickness(1),
CornerRadius = new CornerRadius(10),
Margin = new Thickness(10),
Height = 150D,
Width = 270D,
Child = emptyRectangle,
HorizontalAlignment = HorizontalAlignment.Center,
VerticalAlignment = VerticalAlignment.Center,
Background = this.FindResource("transparentColor")
as LinearGradientBrush
};
//對工作列的Popup界面縮略圖的背景應用圓角
Border host = new Border
CornerRadius = new CornerRadius(8),
Child = visualBorder,
Background = this.FindResource("thumbnailBackground")
as ImageBrush
};
定義一個ToolTip用來宿主界面的縮略圖
ToolTip
//添加一ToolTip，用來宿主子界面的宿略圖
ToolTip visualToolTip = new ToolTip
{
Content = host,
Background = Brushes.Transparent,
BorderBrush = Brushes.Transparent,
Placement = PlacementMode.Top,
HorizontalContentAlignment = HorizontalAlignment.Center,
VerticalContentAlignment = VerticalAlignment.Center,
HasDropShadow = false,
VerticalOffset=3
};
//設計ToolTip的Popup延遲時間為20ms
ToolTipService.SetInitialShowDelay(thumbnail, 20);
thumbnail.ToolTip = visualToolTip;
定義事件，子界面關閉時，從工作列中移除此界面在工作列上的圖示，當在工作列圖示上單擊滑鼠時，實作界面的最大化或者最小化
定義事件
//當打開的子界面關閉時需從工作列移除此界面在工作列上的圖示
child.Closed += delegate
{
this.statusBar.Children.Remove(hostBorder);
};
//在工作列上單擊任務圖示時，最大化或者最小化子界面
hostBorder.MouseLeftButtonDown += delegate(object sender, MouseButtonEventArgs e)
if (e.ClickCount == 1)
{
if (child.WindowState == WindowState.Minimized)
{
//正常顯示子界面
child.WindowState = WindowState.Normal;
child.Topmost = true;
}
else
//最小化子界面
child.WindowState = WindowState.Minimized;
}
這個程式實作起來很簡單，但需要注意的是往工作列裡添加子界面工作列圖示時，應該以從上往下的順序添加，這樣可以避免重複Rendering 邏輯樹的子葉點，