堆叠M，Either和Writer(Stacking M, Either and Writer)

 你应该能够使用Expression Blend 4中包含的新触发器来完成这项工作。例如，有一大堆ne行为/触发器等可以让你对ViewModel中的变化做出反应。 
 
 从Expression Blend功能页面： 
 
 
 
 新行为表达式混合包括新的TranslateZoomRotateBehavior多点触控行为，以及可用于通过触摸在项目之间滚动的PanningItems控件。 Expression Blend还有一个新的触发器，可响应帧更改或暂停或完成SketchFlow动画，称为SketchFlowAnimationTrigger。 Expression Blend具有新的行为集，用于在列表框之间拖动项目，修改菜单导航以及保留屏幕状态，例如SetDataStoreValueAction和DataStoreChangedTrigger。 
 
 
 对FluidMoveBehavior进行了令人兴奋的增强：如果将其应用于同一数据项的不同视图，当项目从一个视图移动到另一个视图时（例如，从列表视图移动到详细信息视图），它会流畅地动画化两个视图之间的过渡。 
 
 
 与使用Model-View-ViewModel模式的应用程序一起使用的新行为包括：CallMethodAction，InvokeCommandAction和DataStateBehavior。 您可以使用这些行为来调用ViewModel上的行为，或者响应对其属性的更改。 
 
 
 条件行为和数据存储您现在可以在原型和生产应用程序中构建条件逻辑，而无需编写代码。 实际上，任何动作都可以与为执行动作必须满足的一组条件相关联。 新的数据存储功能使应用程序变量（例如当前用户的角色）可以被读取和写入，以便有效地，应用程序的不同部分可以通过此共享状态进行通信。 
 
 
 作为此功能的一部分引入的新行为组件包括每个操作的“属性”面板中显示的条件编辑器，允许您操作数据存储中的值的SetDataStoreValueAction操作，以及在数据内部选定的属性时触发的DataStoreChangedTrigger触发器商店改变了。 
 
 
 http://www.microsoft.com/expression/products/Blend_Features.aspx 
 
 干杯，亚历克斯 

you should be able to get this done using the new trigger stuff included in Expression Blend 4. There's a whole bunch of ne behaviors/triggers etc. that let you react to changes in the ViewModel, for instance.
 
From the Expression Blend feature page:
 
 
 
New Behaviors Expression Blend includes the new TranslateZoomRotateBehavior multi-touch Behavior, and a PanningItems control that you can use to scroll between items by using touch. Expression Blend also has a new trigger that responds to a frame change or the pausing or completion of a SketchFlow animation, called the SketchFlowAnimationTrigger. Expression Blend has new sets of Behaviors for dragging items between list boxes, for modifying menu navigation, and for preserving screen states, such as SetDataStoreValueAction and DataStoreChangedTrigger.
 
 
An exciting enhancement has been made to the FluidMoveBehavior: if you apply it to different views of the same data item, when the item moves from one view to another (for example, from a list view to a details view), it fluidly animates the transition between the two views.
 
 
New Behaviors for use with applications that use the Model-View-ViewModel pattern include the following: CallMethodAction, InvokeCommandAction, and DataStateBehavior. You can use these Behaviors to invoke behavior on your ViewModels, or to respond to changes to their properties.
 
 
Conditional Behaviors and the data store You can now build conditional logic into your prototypes and production applications without the need to write code. In fact any action can be associated with a set of conditions that must be met in order to execute the action. The new data store feature enables application variables, such as the current user's role, for example, can be read from and written to so that, effectively, different parts of your application can communicate via this shared state.
 
 
New behavior components introduced as part of this feature include the conditions editor that appears in the Properties panel for every action, a SetDataStoreValueAction action that allows you to manipulate values in your data store, and a DataStoreChangedTrigger trigger that fires whenever a chosen property inside the data store is changed.
 
 
http://www.microsoft.com/expression/products/Blend_Features.aspx
 
Cheers, Alex