DinnerNow中的Work Flow应用(下) --- 订单流程

      做为微软最新技术应用的DEMO。dinnernow使用了: IIS7, ASP.NET Ajax Extensions, LINQ, WCF,
WF,WPF,Windows PowerShell, Card Space以及 .NET Compact Framework. 本文将会继续订餐流程，
来讨论关于WF(Windows Work Flow Foundation)状态机, 在"订单"这一应用场景中的设计思路:)

      继续上一篇中的关于SendActivity的讨论，目前已经完成了订单的创建工作，下面就是要激活该定单流程
的时候了．首先请先双击打开ProcessOrder.xoml文件，找到里面的sendActivity1，它是一个SendActivity,
在这个Activity上面击右键属性，如下图:
    

   　图中的一个非常重要的属性就是ServiceOperationInfo, 它定义了要调用的服务，这里它的属性值为:
DinnerNow.OrderProcess.IUpdateOrder.StartRestaurantOrder．而这个StartRestaurantOrder操作又
是什么东西呢．看来我们还有必要再去检查一下DinnerNow.ServiceHost项目下的 web.config文件，发现如
下服务配置节点:
 <service behaviorConfiguration="WorkflowHostBehavior" name="DinnerNow.OrderProcess.RestaurantOrderWorkflow">
        <endpoint address="" binding="wsHttpContextBinding" contract="DinnerNow.OrderProcess.IUpdateOrder" />
        <endpoint address="mex" binding="mexHttpBinding" contract="IMetadataExchange" />
      </service>
    看来要去RestaurantOrderWorkflow中去找StartRestaurantOrder方法，而RestaurantOrderWorkflow.xoml
本身是一个状态机工作流，如下图：

　　注：如果大家对状态机工作流不清楚，可以参考这篇文章《WF编程》系列之34 - 基本活动:状态活动 

     其中黑线箭头就是定单的流转方向.我们在当前状态机上击右键属性，查看该状态机的设置属性如下图所示：

　　　　

其中的:
    InitialStateName代表初始状态，因为状态机必有一个初始状态，这里它的属性值为：　　
                          RestaurantOrderWorkflowInitialState，
    CompletedStateName代表工作流的结束状态，这里的值为OrderComplete

   　当然光看这些还是无法知道StartRestaurantOrder方法的定义，这时我们要在RestaurantOrderWorkflow.xoml
上击右键，选择"打开方式"，在弹出窗口中选择"XML 编辑器", 在XML中找到下面的节点信息：

< StateActivity x:Name = " RestaurantOrderWorkflowInitialState " >
   < EventDrivenActivity x:Name = " ReceiveRestaurantOrder " >
    < ns0:ReceiveActivity x:Name = " receiveOrder "  CanCreateInstance = " True " >
     < ns0:ReceiveActivity.ServiceOperationInfo >
      < ns0:TypedOperationInfo Name = " StartRestaurantOrder "  ContractType = " {x:Type DinnerNow.OrderProcess.IUpdateOrder} "   />
     </ ns0:ReceiveActivity.ServiceOperationInfo >
     < ns0:ReceiveActivity.ParameterBindings >
      < WorkflowParameterBinding ParameterName = " order " >
       < WorkflowParameterBinding.Value >
        < ActivityBind Name = " RestaurantOrderWorkflow "  Path = " orderToProcess "   />
       </ WorkflowParameterBinding.Value >
      </ WorkflowParameterBinding >
      < WorkflowParameterBinding ParameterName = " context " >
       < WorkflowParameterBinding.Value >
        < ActivityBind Name = " RestaurantOrderWorkflow "  Path = " updateOrderStatusActivity4_conversation1 "   />
       </ WorkflowParameterBinding.Value >
      </ WorkflowParameterBinding >
     </ ns0:ReceiveActivity.ParameterBindings >
     <!--< CodeActivity x:Name = " codeActivity1 "  ExecuteCode = " AcceptOrderCode "   />-->
    </ ns0:ReceiveActivity >
    < ns1:UpdateOrderStatusActivity orderStatus = " {ActivityBind RestaurantOrderWorkflow,Path=orderStatus} "  IncomingOrder = " {ActivityBind RestaurantOrderWorkflow,Path=orderToProcess} "  conversation = " {ActivityBind RestaurantOrderWorkflow,Path=updateOrderStatusActivity4_conversation1} "  x:Name = " updateOrderStatusActivity4 "   />
    < SetStateActivity x:Name = " setStateActivity3 "  TargetStateName = " OrderCooking "   />
   </ EventDrivenActivity >
  </ StateActivity >

　
这里需要解释一下，上面代码的第一行就是我们看到的状态机的初始化活动的名称，即这个StateActivity就是初始
化活动，而EventDrivenActivity x:Name="ReceiveRestaurantOrder"代表当发生ReceiveRestaurantOrder事件时即启动
当前的状态活动并将当前的状态转换到下一个新的状态（即上面代码中的TargetStateName="OrderCooking"属性值）．
当然状态机本身是需要有实例来运行的，所以CanCreateInstance="True"．

接下来我们看到了下面这一行代码：
<ns0:TypedOperationInfo Name="StartRestaurantOrder" ContractType="{x:Type DinnerNow.OrderProcess.IUpdateOrder}" />
到这里，我们找到了StartRestaurantOrder方法的声明位置，那StartRestaurantOrder运行代码又在何处呢，其实
我们可以从上面代码中找到如下一行代码:

< ns1:UpdateOrderStatusActivity orderStatus = " {ActivityBind RestaurantOrderWorkflow,Path=orderStatus} "  IncomingOrder = " {ActivityBind RestaurantOrderWorkflow,Path=orderToProcess} "  conversation = " {ActivityBind RestaurantOrderWorkflow,Path=updateOrderStatusActivity4_conversation1} "  x:Name = " updateOrderStatusActivity4 "   />

　　它指示当前状态初始化后要执行UpdateOrderStatusActivity.
     注：该类位于Workflow/UpdateOrderStatusActivity.cs文件,见下面代码：

public   partial   class  UpdateOrderStatusActivity: Activity
{
      public   static  DependencyProperty IncomingOrderProperty  =  DependencyProperty.Register( " IncomingOrder " ,  typeof (DinnerNow.Business.Data.RestaurantOrder),  typeof (UpdateOrderStatusActivity));
      public   static  DependencyProperty orderStatusProperty  =  DependencyProperty.Register( " orderStatus " ,  typeof (System.String),  typeof (UpdateOrderStatusActivity));
      public   static  DependencyProperty conversationProperty  =  DependencyProperty.Register( " conversation " ,  typeof (System.Collections.Generic.Dictionary < string ,  string > ),  typeof (UpdateOrderStatusActivity));

     [BrowsableAttribute( true )]
     [CategoryAttribute( " Parameters " )]
     [DesignerSerializationVisibility(DesignerSerializationVisibility.Visible)]
      public  System.Collections.Generic.Dictionary < string , string >  conversation
     {
          get
         {
              return  ((System.Collections.Generic.Dictionary < string , string > )( base .GetValue(UpdateOrderStatusActivity.conversationProperty)));
         }
          set
         {
              base .SetValue(UpdateOrderStatusActivity.conversationProperty, value);
         }
     }


     [Description( " Restaurant Order " )]
     [Browsable( true )]
     [Category( " Order " )]
     [DesignerSerializationVisibility(DesignerSerializationVisibility.Visible)]
      public  DinnerNow.Business.Data.RestaurantOrder IncomingOrder
     {
          get
         {
              return  ((DinnerNow.Business.Data.RestaurantOrder)( base .GetValue(UpdateOrderStatusActivity.IncomingOrderProperty)));
         }
          set
         {
              base .SetValue(UpdateOrderStatusActivity.IncomingOrderProperty, value);
         }
     }
     [DesignerSerializationVisibilityAttribute(DesignerSerializationVisibility.Visible)]
     [BrowsableAttribute( true )]
     [CategoryAttribute( " Parameters " )]
      public   string  orderStatus
     {
          get
         {
              return  ((System.String)( base .GetValue(UpdateOrderStatusActivity.orderStatusProperty)));
         }
          set
         {
              base .SetValue(UpdateOrderStatusActivity.orderStatusProperty, value);
         }
     }

     public  UpdateOrderStatusActivity()
       {
            InitializeComponent();
       }

         protected   override  ActivityExecutionStatus Execute(ActivityExecutionContext executionContext)
        {
            OrderService service  =   new  OrderService();
            service.UpdateOrderStatus(IncomingOrder, orderStatus,  this .WorkflowInstanceId);
             return  ActivityExecutionStatus.Closed;
        }
}

　　上面代码中的conversation属性和IncomingOrder属性所绑定的就是我在上一篇文章所说的SendActivity所发
送过来的参数，其中conversation就是那个Context上下文．当然这里还有一个属性orderStatus，其实它的属性值
是在相应的StateActivity中已被设置好了．以当前的"RestaurantOrderWorkflowInitialState"为例，其属性值为：

orderStatus="{ActivityBind RestaurantOrderWorkflow,Path=orderStatus}"

其中的Path=orderStatus即指向RestaurantOrderWorkflow.xoml.cs文件中的属性声明：
public static string orderStatus = "New Order";
     这样当运行上面的Execute方法之后，当前订单的状态就会更新为New Order.
  
     上面代码中的UpdateOrderStatus方法声明如下: 

public   bool  UpdateOrderStatus(DinnerNow.Business.Data.RestaurantOrder restaurantOrder,  string  status, Guid workflowId)
{
     using  (Business.OrderProcessing op  =   new  DinnerNow.Business.OrderProcessing())
    {
         return  op.UpdateOrderStatus(restaurantOrder, status, workflowId);
    }
}

    上面代码中的op.UpdateOrderStatus会执行下面的LINQ语句：   

public   bool  UpdateOrderStatus(DinnerNow.Business.Data.RestaurantOrder restaurantOrder,  string  status, Guid WorkflowId)
{
    var orderItems  =  from od  in  db.OrderDetails
                      where  od.RestaurantId  ==  restaurantOrder.RestaurantId
                      &&  od.OrderId  ==  restaurantOrder.OrderId
                     select  new
                     {
                         OrderDetailId  =  od.OrderDetailId
                     };

     foreach  (var orderItemId  in  orderItems)
    {
        var orderItem  =  db.OrderDetails.Single(oi  =>  oi.OrderDetailId  ==  orderItemId.OrderDetailId);
        orderItem.WorkflowId  =  WorkflowId;
        orderItem.Status  =  status;
        orderItem.StatusUpdatedTime  =  DateTime.Now;
    }
    db.SubmitChanges();

     return   true ;
}

　　当然定单的状态会按图中所标记的箭头方向转向到下一个状态，在XML中可以在当前的StateActivity
节点中找到下面的内容：
<SetStateActivity x:Name="setStateActivity3" TargetStateName="OrderCooking" />

　　其中的TargetStateName属性值即是下一个状态名称，其内容如下：

< StateActivity x:Name = " OrderCooking " >
   < StateInitializationActivity x:Name = " orderCookingInitialization " >
    < ns1:UpdateOrderStatusActivity orderStatus = " {ActivityBind RestaurantOrderWorkflow,Path=orderStatusCooking} "  IncomingOrder = " {ActivityBind RestaurantOrderWorkflow,Path=orderToProcess} "  conversation = " {x:Null} "  x:Name = " UpdateOrderStatusActivity1 "   />
   </ StateInitializationActivity >
   < EventDrivenActivity x:Name = " OrderCooked " >
    < ns0:ReceiveActivity x:Name = " receiveOrderReadyForPickup " >
     < ns0:ReceiveActivity.ServiceOperationInfo >
      < ns0:TypedOperationInfo Name = " OrderReadyForPickup "  ContractType = " {x:Type DinnerNow.OrderProcess.IUpdateOrder} "   />
     </ ns0:ReceiveActivity.ServiceOperationInfo >
     < ns0:ReceiveActivity.ParameterBindings >
      < WorkflowParameterBinding ParameterName = " order " >
       < WorkflowParameterBinding.Value >
        < ActivityBind Name = " RestaurantOrderWorkflow "  Path = " orderToProcess "   />
       </ WorkflowParameterBinding.Value >
      </ WorkflowParameterBinding >
     </ ns0:ReceiveActivity.ParameterBindings >
    </ ns0:ReceiveActivity >
    < SetStateActivity x:Name = " setStateOrderReadyForPickup "  TargetStateName = " OrderReadyForPickup "   />
   </ EventDrivenActivity >
  </ StateActivity >

　　在这里, 我们看到了与刚才的初始化状态相类似的状态节点配置，并且它也有TargetStateName，其属性值
为OrderReadyForPickup，看到这里感觉状态机越来越像是一个链表，它指定着状态传递的方向．而最终的完成
状态就是状态机工作流中的CompletedStateName属性值．上面的状态活动的EventDrivenActivity为：
OrderReadyForPickup，而这个驱动事件又是那个请求发出的呢？这里我们需要再打开另外一个解决方案，
它位于安装目录下/solution/DinnerNow - Kiosk/solution/DinnerNow - Kiosk.sln,　我们编译这个WPF项目，
得到下面的运行截图:

　　    　

当我们选取其中的一个定单之后，显示该订单的一些详细信息如下图：

　　

我们在这里通过下拉框更新了当前订单的状态，其最终的C#运行代码如下(OrderStatusWindow.xaml.cs):   

   ..

    switch  (newStatusText.Trim())
   {
      case "New Order":
          // we need to get the selected order
          // do nothing
          break;
      case "Ready for pickup":
          orderUpdateClient.OrderReadyForPickup(new RestaurantOrder() { OrderId = new Guid(this.SelectedOrder.OrderIdentifier), RestaurantId = this.SelectedOrder.RestaurantId });
          break;
      case "Out for Delivery":
          orderUpdateClient.OrderPickedUp(new RestaurantOrder() { OrderId = new Guid(this.SelectedOrder.OrderIdentifier), RestaurantId = this.SelectedOrder.RestaurantId }, Guid.NewGuid());
          break;
      case "Delivered":
          orderUpdateClient.OrderDelivered(new RestaurantOrder() { OrderId = new Guid(this.SelectedOrder.OrderIdentifier), RestaurantId = this.SelectedOrder.RestaurantId });
          break;
  } ;

　　这里，还有一点需要说明的是在OrderDelivered这个StateActivity中的一些信息，因为在这个状态活动中
有对上一篇文章中所说的ProcessOrder（顺序工作流）的信息发送，请看下面代码段：

< StateActivity x:Name = " OrderDelivered " >
   < StateInitializationActivity x:Name = " OrderDeliveredInitialization " >
    < ns1:UpdateOrderStatusActivity orderStatus = " {ActivityBind RestaurantOrderWorkflow,Path=orderStatusOrderDelivered} "  IncomingOrder = " {ActivityBind RestaurantOrderWorkflow,Path=orderToProcess} "  conversation = " {x:Null} "  x:Name = " updateOrderStatusActivity5 "   />
    < ns0:SendActivity x:Name = " restaurantOrderComplete " >
     < ns0:SendActivity.ServiceOperationInfo >
      < ns0:TypedOperationInfo Name = " RestaurantOrderComplete "  ContractType = " {x:Type DinnerNow.OrderProcess.IProcessOrder} "   />
     </ ns0:SendActivity.ServiceOperationInfo >
     < ns0:SendActivity.ChannelToken >
      < ns0:ChannelToken Name = " completeOrderToken "  EndpointName = " WSHttpContextBinding_IProcessOrder "   />
     </ ns0:SendActivity.ChannelToken >
    </ ns0:SendActivity >
    < SetStateActivity x:Name = " setStateActivity4 "  TargetStateName = " OrderComplete "   />
   </ StateInitializationActivity >
  </ StateActivity >

 　　其中下面这一行就是要使用的ProcessOrder工作流中的操作信息：
    <ns0:TypedOperationInfo Name="RestaurantOrderComplete" ContractType="{x:Type DinnerNow.OrderProcess.IProcessOrder}" />

这样就会将ProcessOrder流程走完了．并且定单的状态也会变为OrderComplete。

     好了，订单状态的更新流转已介绍的差不多了，不过这里还有一个功能没有介绍，那就是DinnerNow提供了
Window Mobile接收编辑发送功能，而这个功能也是订单流程的一部分，但这块内容与当前本文所讨论的技术没
太大关联性．还是留到以后有时间再与大家聊一聊吧．

　　好的，今天的内容就先告一段落，大家如果有兴趣，欢迎在回复中进行讨论:)