学步园

“BitmapCacheBrush总是从一个目标元素的缓存或者通过BitmapCache 属性定义的缓存来渲染并且BitmapCacheBrush类忽略以下位于根Visual的属性：VisualOffset，VisualTransform，VisualClip，VisualEffect，VisualOpacity，VisualOpacity。这种行为有别于VisualBrush类。”

－－http://social.msdn.microsoft.com/Forums/zh-CN/wpfzhchs/thread/96a254b8-ab18-4096-9c9e-255822decd2f

测试代码（部分取自MSDN）

<Window<br /> xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"<br /> xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"<br /> Title="Window1"<br /> xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"<br /> Height="300" Width="300" ><br /> <Window.Resources><br /> <RichTextBox x:Key="cachedRichTextBox" ><br /> <RichTextBox.CacheMode><br /> <BitmapCache EnableClearType="True" RenderAtScale="1" SnapsToDevicePixels="True" /><br /> </RichTextBox.CacheMode><br /> <FlowDocument><br /> <Paragraph><br /> <Run FontSize="16" Text="0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ" /><br /> </Paragraph><br /> </FlowDocument><br /> </RichTextBox><br /> <BitmapCacheBrush x:Key="cachedRichTextBoxBrush" Target="{StaticResource cachedRichTextBox}"><br /> <BitmapCacheBrush.BitmapCache><br /> <BitmapCache EnableClearType="False" RenderAtScale="0.4" SnapsToDevicePixels="False" /><br /> </BitmapCacheBrush.BitmapCache><br /> </BitmapCacheBrush> </p> <p> <BitmapCacheBrush x:Key="cachedr1" Target="{Binding ElementName=r1}"><br /> <BitmapCacheBrush.BitmapCache><br /> <BitmapCache EnableClearType="False" RenderAtScale="0.4" SnapsToDevicePixels="False" /><br /> </BitmapCacheBrush.BitmapCache><br /> </BitmapCacheBrush> </p> <p> <VisualBrush x:Key="visualr1" Visual="{Binding ElementName=r1}"></VisualBrush><br /> </Window.Resources><br /> <Grid><br /> <Grid.RowDefinitions><br /> <RowDefinition Height="*" /><br /> <RowDefinition Height="*" /><br /> <RowDefinition Height="*" /><br /> <RowDefinition Height="*" /><br /> <RowDefinition Height="*" /><br /> </Grid.RowDefinitions><br /> <Grid.ColumnDefinitions><br /> <ColumnDefinition Width="*" /><br /> <ColumnDefinition Width="*" /><br /> <ColumnDefinition Width="*" /><br /> <ColumnDefinition Width="*" /><br /> <ColumnDefinition Width="*" /><br /> </Grid.ColumnDefinitions><br /> <Button Background="{StaticResource cachedRichTextBoxBrush}" Content="Button" Name="button1" FontWeight="Bold" /><br /> <Button Background="{StaticResource cachedRichTextBoxBrush}" Content="Button" Name="button2" Grid.Column="1" FontWeight="Bold" /><br /> <Button Background="{StaticResource cachedr1}" Content="Button" Name="button3" Grid.Column="2" FontWeight="Bold" /><br /> <Button Background="{StaticResource cachedr1}" Content="Button" Name="button4" Grid.Column="3" FontWeight="Bold" /><br /> <Button Background="{StaticResource cachedRichTextBoxBrush}" Content="Button" Name="button5" Grid.Column="4" FontWeight="Bold" /><br /> <Button Background="{StaticResource cachedRichTextBoxBrush}" Content="Button" Name="button6" Grid.Row="1" FontWeight="Bold" /><br /> <Button Background="{StaticResource cachedr1}" Content="Button" Grid.Column="1" Name="button7" Grid.Row="1" FontWeight="Bold" /><br /> <Button Background="{StaticResource cachedr1}" Content="Button" Grid.Column="2" Name="button8" Grid.Row="1" FontWeight="Bold" /><br /> <Button Background="{StaticResource cachedRichTextBoxBrush}" Content="Button" Grid.Column="3" Name="button9" Grid.Row="1" FontWeight="Bold" /><br /> <Button Background="{StaticResource cachedRichTextBoxBrush}" Content="Button" Grid.Column="4" Name="button10" Grid.Row="1" FontWeight="Bold" /><br /> <Button Background="{StaticResource cachedr1}" Content="Button" Name="button11" Grid.Row="2" FontWeight="Bold" /><br /> <Button Background="{StaticResource cachedr1}" Content="Button" Grid.Column="1" Name="button12" Grid.Row="2" FontWeight="Bold" /><br /> <Button Background="{StaticResource cachedRichTextBoxBrush}" Content="Button" Grid.Column="2" Name="button13" Grid.Row="2" FontWeight="Bold" /><br /> <Button Background="{StaticResource cachedRichTextBoxBrush}" Content="Button" Grid.Column="3" Name="button14" Grid.Row="2" FontWeight="Bold" /><br /> <Button Background="{StaticResource visualr1}" Content="Button" Grid.Column="4" Name="button15" Grid.Row="2" FontWeight="Bold" /><br /> <Button Background="{StaticResource visualr1}" Content="Button" Name="button16" Grid.Row="3" FontWeight="Bold" /><br /> <Button Background="{StaticResource cachedRichTextBoxBrush}" Content="Button" Grid.Column="1" Name="button17" Grid.Row="3" FontWeight="Bold" /><br /> <Button Background="{StaticResource cachedRichTextBoxBrush}" Content="Button" Grid.Column="2" Name="button18" Grid.Row="3" FontWeight="Bold" /><br /> <Button Background="{StaticResource visualr1}" Content="Button" Grid.Column="3" Name="button19" Grid.Row="3" FontWeight="Bold" /><br /> <Button Background="{StaticResource visualr1}" Content="Button" Grid.Column="4" Name="button20" Grid.Row="3" FontWeight="Bold" /><br /> <Button Background="{StaticResource cachedRichTextBoxBrush}" Content="Button" Name="button21" Grid.Row="4" FontWeight="Bold" /><br /> <Button Background="{StaticResource cachedRichTextBoxBrush}" Content="Button" Grid.Column="1" Name="button22" Grid.Row="4" FontWeight="Bold" /><br /> <Button Background="{StaticResource visualr1}" Content="Button" Grid.Column="2" Name="button23" Grid.Row="4" FontWeight="Bold" /><br /> <Button Background="{StaticResource visualr1}" Content="Button" Grid.Column="3" Name="button24" Grid.Row="4" FontWeight="Bold" /><br /> <Button Background="{StaticResource cachedRichTextBoxBrush}" Content="Button" Grid.Column="4" Name="button25" Grid.Row="4" FontWeight="Bold" /><br /> <RichTextBox Name="r1"><br /> <RichTextBox.CacheMode><br /> <BitmapCache EnableClearType="True" RenderAtScale="1" SnapsToDevicePixels="True" /><br /> </RichTextBox.CacheMode><br /> <FlowDocument><br /> <Paragraph><br /> <Run Foreground="Red" FontSize="16" Text="0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ" /><br /> </Paragraph><br /> </FlowDocument><br /> </RichTextBox><br /> </Grid><br /> </Window> 

效果图：