WF4工作流设计器模型对Undo和Redo的支持

WF4工作流设计器模型对Undo和Redo的支持2010-12-27 博客园生鱼片WF4的设计器模型中提供了UndoEngine类，提供设计时的Undo（撤销）和Redo（重做）功能。我们可以调用工作设计器的服务来启用Undo和Redo功能。主要涉及到下面几个类：

下面一个简单例子说明

1.WPF的Xaml部分如下：

<Window x:Class="CaryUndo.MainWindow"
         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
         xmlns:sadt="clr-namespace:System.Activities.Presentation.Toolbox;assembly=System.Activities.Presentation"
         xmlns:sys="clr-namespace:System;assembly=mscorlib"
         Title="MainWindow" Height="350" Width="525">
     <Window.CommandBindings>
         <CommandBinding Command="Undo" Executed="UndoHandle" />
         <CommandBinding Command="Redo" Executed="RedoHandle" />
     </Window.CommandBindings>
     <Window.Resources>
         <sys:String x:Key="AssemblyName">System.Activities, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35</sys:String>
     </Window.Resources>
     <Grid>
         <Grid.ColumnDefinitions>
             <ColumnDefinition Width="2*"/>
             <ColumnDefinition Width="7*"/>
             <ColumnDefinition Width="3*"/>
         </Grid.ColumnDefinitions>
         <Border Grid.Column="0">
             <sadt:ToolboxControl>
                 <sadt:ToolboxCategory CategoryName="Basic">
                     <sadt:ToolboxItemWrapper AssemblyName="{StaticResource AssemblyName}" >
                         <sadt:ToolboxItemWrapper.ToolName>
                             System.Activities.Statements.Sequence
                         </sadt:ToolboxItemWrapper.ToolName>
                     </sadt:ToolboxItemWrapper>
                     <sadt:ToolboxItemWrapper  AssemblyName="{StaticResource AssemblyName}">
                         <sadt:ToolboxItemWrapper.ToolName>
                             System.Activities.Statements.WriteLine
                         </sadt:ToolboxItemWrapper.ToolName>
                     </sadt:ToolboxItemWrapper>
                     <sadt:ToolboxItemWrapper  AssemblyName="{StaticResource AssemblyName}">
                         <sadt:ToolboxItemWrapper.ToolName>
                             System.Activities.Statements.Pick
                         </sadt:ToolboxItemWrapper.ToolName>
                     </sadt:ToolboxItemWrapper>
                 </sadt:ToolboxCategory>
             </sadt:ToolboxControl>
         </Border>
         <Border Grid.Column="1" Name="DesignerBorder"></Border>
         <Border Grid.Column="2" Name="PropertyBorder"/>
         <Button Content="Undo" Command="Undo" Height="23" HorizontalAlignment="Left" Margin="9,179,0,0" Name="button1" VerticalAlignment="Top" Width="75" />
         <Button Content="Redo" Command="Redo" Height="23" HorizontalAlignment="Left" Margin="9,218,0,0" Name="button2" VerticalAlignment="Top" Width="75" />
     </Grid>
</Window>