試用Workflow開發WPF應用程序

研究了半個月的《WF高級程序設計》，我覺得這個框架做的太有價值了，又將WCF和Web服務結合起來了，提高了它的應用領域。工作流使我們能夠輕松地建模系統，實現真正邏輯意義上的人機交互功能。這在游戲開發中特別有用，而且將開發人員從架構的角度來設計程序，提高程序設計的邏輯性和可讀性。由于書上的例子都是在WinForm和控制臺上的，所以我覺得有必要運用到WPF開發中。由于WPF架構與WinForm許多的差異，所以我試著做了一個WPF的隨機選數游戲來體驗一下WPF與WF的結合。

由于本例子主要目的在于體現一個順序機制，按理說應該是用順序工作流來處理這個機制，考慮到以后的擴展，我選擇了狀態機工作流。我們先來了解一下狀態機工作流，所謂“狀態機工作流”是指一組應用程序狀態以及狀態之間的可能的轉換。每個狀態都可以處理多個外部事件，外部事件能夠觸發器子活動的執行，而自活動又可能包含一個到其他狀態的轉換。

先來看一下工作流機制：

一、建立一個空的工作流項目[一個dll]

1、定義一個公共的接口

在這個接口中設計了五個事件和一個方法。定義的事件是為了提供給工作流的使用。

Generic.xamlusing System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Workflow.Activities;

namespace SelectGameWorkflow
{
    [ExternalDataExchange]
    public interface IPointSelect
	{
        /// <summary>
        /// 開a始?選?擇?事?件t，?以?得?到?的?數簓最?大洙?者?獲?勝骸?
        /// </summary>
        event EventHandler<ExternalDataEventArgs> StartSelect;

        /// <summary>
        /// 結á束?選?擇?事?件t
        /// </summary>
        event EventHandler<ExternalDataEventArgs> StopSelect;

        /// <summary>
        /// 第臺?一?個?玩?家ò開a始?選?
        /// </summary>
        event EventHandler<ExternalDataEventArgs> First;

        /// <summary>
        /// 第臺?二t個?玩?家ò開a始?選?
        /// </summary>
        event EventHandler<ExternalDataEventArgs> Second;

        /// <summary>
        /// 第臺?三▂個?玩?家ò開a始?選?，?并￠且ò結á束?游?戲·
        /// </summary>
        event EventHandler<ExternalDataEventArgs> Third;


        /// <summary>
        /// 玩?家ò結á束?
        /// </summary>
        event EventHandler<ExternalDataEventArgs> Completed;
        

        /// <summary>
        /// 將?消?息￠傳?遞蘗到?宿T主÷
        /// </summary>
        /// <param name="message"></param>
        void SendMessage(string message);
	}
}

2、實現接口服務的PointSelectService類，這個外部服務類提供一組事件調用方法和一個事件，供宿主使用，相應的代碼如下：

代碼

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Workflow.Activities;
using System.Workflow.Runtime;

namespace SelectGameWorkflow
{
    /// <summary>
    /// 實現服務接口類
    /// </summary>
    public     class PointSelectService:IPointSelect 
    {
        #region IPointSelect 成員

        public event EventHandler<System.Workflow.Activities.ExternalDataEventArgs> StartSelect;

        public event EventHandler<System.Workflow.Activities.ExternalDataEventArgs> StopSelect;

        public event EventHandler<System.Workflow.Activities.ExternalDataEventArgs> First;

        public event EventHandler<System.Workflow.Activities.ExternalDataEventArgs> Second;

        public event EventHandler<System.Workflow.Activities.ExternalDataEventArgs> Third;

        public event EventHandler<ExternalDataEventArgs> Completed;

        /// <summary>
        /// 調用宿主的事件
        /// </summary>
        /// <param name="message"></param>
        public void SendMessage(string message)
        {
            if (MessageReceived != null)
                MessageReceived(this, new MessageReceivedEventArgs(WorkflowEnvironment.WorkflowInstanceId, message));
        }

        #endregion

        /// <summary>
        /// 
        /// 工作流使用的事件
        /// </summary>
        public event EventHandler<MessageReceivedEventArgs> MessageReceived;

        #region 以下定義了一組供宿主使用的方法


        public void OnStartSelect(ExternalDataEventArgs e)
        {
            if (StartSelect != null)
                StartSelect(null, e);
        }

        public void OnStopSelect(ExternalDataEventArgs e)
        {
            if (StopSelect != null)
                StopSelect(null, e);
        }

        public void OnFirst(ExternalDataEventArgs e)
        {
            if (First != null)
                First(null, e);
        }

        public void OnSecond(ExternalDataEventArgs e)
        {
            if (Second != null)
                Second(null, e);
        }

        public void OnThird(ExternalDataEventArgs e)
        {
            if (Third != null)
                Third(null, e);
        }

        public void OnCompleted(ExternalDataEventArgs e)
        {
            if (Completed != null)
                Completed(null, e);
        }
        #endregion

    }

這里還定義了一個EventArgs的派生類來傳遞服務消息：

代碼

   /// <summary>
    /// 把工作流的相應消息發送到本地服務中
    /// </summary>
    [Serializable]
    public class MessageReceivedEventArgs : ExternalDataEventArgs
    {
        public string Message { get; set; }


        /// <summary>
        /// 在構造器中傳遞消息，其中會將工作流的ID傳遞到基類中
        /// </summary>
        /// <param name="instanceId"></param>
        /// <param name="message"></param>
        public MessageReceivedEventArgs(Guid instanceId, string message):base(instanceId )
        {
            this.Message = message;
        }
    }

3、在剛才的項目中添加一個狀態機工作流：

這里面定義了一組狀態事件處理，如表所示：

除了DoneState狀態之外，每個State都有定義了三個活動，按順序分別是：

handleExternalEventActivity、callExternalMethodActivity、setStateActivity，可以分別設置他們的接口、事件和方法，如圖所示：

整個狀態機的工作流視圖如下：

現在我們可以重新生成動態庫了，得到SelectGameWorkflow.dll文件

二、添加一個WPF項目作為工作流的宿主，這個WPF命名為SelectGameWPF，

1、先設計界面，效果如下：

相應的XAML代碼如下：

代碼

<Window x:Class="SelectGameWPF.Window1"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" 
    Title="碰手氣" Height="300" Width="300" xmlns:my="clr-namespace:C4F.VistaP2P.WPF.Chat;assembly=C4F_P2PWPFControls" Loaded="Window_Loaded">
    <Grid Background="LightBlue" >
        <Grid.RowDefinitions>
            <RowDefinition Height="50"/>
            <RowDefinition/>
        </Grid.RowDefinitions>
        <TextBlock Height="58"  Text="{Binding Number}" x:Name="numberText" VerticalAlignment="Top" FontSize="48" HorizontalAlignment="Center" FontFamily="Broadway">
            <TextBlock.OpacityMask>
                <LinearGradientBrush EndPoint="0.5,1" StartPoint="0.5,0">
                    <GradientStop Color="#E5000000" Offset="0"/>
                    <GradientStop Color="#99FFFFFF" Offset="1"/>
                </LinearGradientBrush>
            </TextBlock.OpacityMask>
            <TextBlock.Foreground>
                <LinearGradientBrush EndPoint="0.5,1" StartPoint="0.5,0">
                    <GradientStop Color="#FFED7B69" Offset="0"/>
                    <GradientStop Color="#CCFFFFFF" Offset="0.385"/>
                    <GradientStop Color="#E8E78851" Offset="0.931"/>
                </LinearGradientBrush>
            </TextBlock.Foreground>
        </TextBlock>
        <GroupBox HorizontalAlignment="Left" VerticalAlignment="Top" Grid.Row="1">
            <GroupBox.Header>
                <TextBlock Text="控制"/>
            </GroupBox.Header>
            <StackPanel  Width="100" x:Name="controlButtons">
                    <Button x:Name="startBtn"  Content="開  始" Height="40" Margin="5,20" Click="startBtn_Click"/>
                    <Button x:Name="stopBtn"  Content="停  止" Height="40" Margin="5,0,5,20" Click="stopBtn_Click"/>
                </StackPanel>
        </GroupBox>
        <GroupBox x:Name="control" Header="玩家" HorizontalAlignment="Right" VerticalAlignment="Top" Grid.Row="1">
            <StackPanel  Width="100" x:Name="playerButtons">
                <Button x:Name="firstBtn"  Content="第一個玩家" Height="40" Margin="5,20" Click="firstBtn_Click"/>
                <Button x:Name="secondBtn"  Content="第二個玩家" Height="40" Margin="5,0,5,20" Click="secondBtn_Click"/>
                <Button x:Name="thirdBtn"  Content="第三個玩家" Height="40" Margin="5,0,5,20" Click="thirdBtn_Click"/>
            </StackPanel>
        </GroupBox>
        <TextBlock Grid.Row="1" Height="23" HorizontalAlignment="Left"  Name="textBlock1" Text="{Binding Message}" VerticalAlignment="Bottom" Width="160" />
    </Grid>
</Window>

2、添加兩個更新界面的依賴屬性：

代碼

      #region 定義一個隨機數和消息
        public static readonly DependencyProperty NumberProperty = DependencyProperty.Register("Number", typeof(int), typeof(Window1), new PropertyMetadata(0));
        public static readonly DependencyProperty MessageProperty = DependencyProperty.Register("Message", typeof(string), typeof(Window1), new PropertyMetadata(string.Empty));

        public int Number {
            get { return (int)GetValue(NumberProperty); }
            set { SetValue(NumberProperty, value); }
        }

        public string Message {
            get { return (string)GetValue(MessageProperty); }
            set { SetValue(MessageProperty, value); }
        }
        #endregion

為了能夠在UI線程中更新視覺元素，我們使用了和WinForm的Invoke異步調用的相同的Dispatcher類的BeginInvoke方法：

如下所示：

代碼

     private delegate void UpdateDelegate();

  /// <summary>
        /// 在指定的時間段內產生隨機數
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        void timer_Tick(object sender, EventArgs e)
        {
            ///將數字呈現到前臺
            UpdateDelegate theDelg = () =>
            {
                Number = rand.Next(100);
            };
            Dispatcher.BeginInvoke(theDelg, null);
        }

其他的更新方式如上面所示

3、接下來調用工作流項目以及將上面的SelectGameService服務加入到運行時：

代碼

     /// <summary>
        /// 初始化工作流服務
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void Window_Loaded(object sender, RoutedEventArgs e)
        {
            manager = new WorkflowRuntimeManager(new WorkflowRuntime());

            //在轉換到新的狀態時發生
            manager.WorkflowRuntime.WorkflowIdled += new EventHandler<WorkflowEventArgs>(WorkflowRuntime_WorkflowIdled);
            AddServices(manager.WorkflowRuntime);
        }

        /// <summary>
        /// 處理Idle事件
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        void WorkflowRuntime_WorkflowIdled(object sender, WorkflowEventArgs e)
        {
            UpdateDelegate theDelg = () =>
            {
                EnableEventButton(false);

                //得到內部隊列信息
                ReadOnlyCollection<WorkflowQueueInfo> queueInfoData = instanceWrapper.WorkflowInstance.GetWorkflowQueueData();

                if (queueInfoData != null) {
                    foreach (WorkflowQueueInfo  info in queueInfoData) {
                        EventQueueName eventQueue = info.QueueName as EventQueueName;

                        if (eventQueue == null)
                            break;

                        EnableButtonForEvent(eventQueue.MethodName);
                    }
                }
            };

            Dispatcher.BeginInvoke(theDelg, null);
        }

        /// <summary>
        /// 根據事件名啟用按鈕
        /// </summary>
        /// <param name="p"></param>
        private void EnableButtonForEvent(string eventName)
        {
            var buttons1 = controlButtons.Children;
            var buttons2 = playerButtons.Children;

            foreach (Button btn in buttons1) {
                if (btn.Tag.ToString() == eventName)
                    btn.IsEnabled = true;
            }
            foreach (Button btn in buttons2)
            {
                if (btn.Tag.ToString() == eventName)
                    btn.IsEnabled = true;
            }
        }

        /// <summary>
        /// 將服務添加到工作流運行時
        /// </summary>
        /// <param name="workflowRuntime"></param>
        private void AddServices(WorkflowRuntime workflowRuntime)
        {
            ExternalDataExchangeService exchangeService = new ExternalDataExchangeService();
            workflowRuntime.AddService(exchangeService);

            pointSelectService = new PointSelectService();
            pointSelectService.MessageReceived += new EventHandler<MessageReceivedEventArgs>(pointSelectService_MessageReceived);
            exchangeService.AddService(pointSelectService);
        }

        void pointSelectService_MessageReceived(object sender, MessageReceivedEventArgs e)
        {
            UpdateDelegate theDelg = () =>
            {
                Message = e.Message;
            };

            //保存工作流實例標識
           System.Threading.Thread.Sleep(1000);
           timer.Start();
           instanceId = e.InstanceId;

           Dispatcher.BeginInvoke(theDelg, null);
        }
    }

4、初始化按鈕狀態和定時器

代碼

   public Window1()
        {
            InitializeComponent();
            timer = new DispatcherTimer();
            timer.Interval = new TimeSpan(0, 0, 0, 0, 300);
            timer.Tick += new EventHandler(timer_Tick);
            rand = new Random();

            //設置按鈕標識
            startBtn.Tag = "StartSelect";
            stopBtn.Tag = "StopSelect";
            firstBtn.Tag = "First";
            secondBtn.Tag = "Second";
            thirdBtn.Tag = "Third";

            EnableEventButton(false);

            DataContext = this;
        }

        /// <summary>
        /// 控制按鈕的狀態
        /// </summary>
        /// <param name="p"></param>
        private void EnableEventButton(bool p)
        {
            stopBtn.IsEnabled = p;
            firstBtn.IsEnabled = p;
            secondBtn.IsEnabled = p;
            thirdBtn.IsEnabled = p;
        }

5、添加所有按鈕的Click事件，其目的是為了調用服務的方法和宿主本身的定時器的，如下所示：

代碼

   #region Click events

        private void firstBtn_Click(object sender, System.Windows.RoutedEventArgs e)
        {
            // TODO: Add event handler implementation here.
            try
            {
                pointSelectService.OnFirst(GetEventArgs());
                timer.Stop();
                if (Number > temp)
                {
                    temp = Number;
                    tempPlayer = "First";
                }
            }
            catch(Exception ex) {
                HandleException(ex);
            }
        }

        private void secondBtn_Click(object sender, System.Windows.RoutedEventArgs e)
        {
            // TODO: Add event handler implementation here.
            try
            {
                pointSelectService.OnSecond(GetEventArgs());
                timer.Stop();

                if (Number > temp)
                {
                    temp = Number;
                    tempPlayer = "Second";
                }
            }
            catch (Exception ex) {
                HandleException(ex);
            }
        }

        private void thirdBtn_Click(object sender, System.Windows.RoutedEventArgs e)
        {
            // TODO: Add event handler implementation here.
            try
            {
                pointSelectService.OnThird(GetEventArgs());
                timer.Stop();

                if (Number > temp)
                {
                    temp = Number;
                    tempPlayer = "Third";
                }

                if (tempPlayer != string.Empty)
                {
                    UpdateDelegate theDelg = () =>
                    {
                        Message = tempPlayer + "得到最大數: " + temp.ToString();
                    };
                    Dispatcher.BeginInvoke(theDelg, null);
                }
            }
            catch (Exception ex) {
                HandleException(ex);
            }
        }

        #endregion

至此，整個工程全部完成，現在在啟動應用程序以后，我們就可以按如開頭的工作流圖的順序依次：Start-First-Second-Third-Start。

其實這個程序我們可以演化到多用戶順序執行程序，如網絡麻將、斗地主等互動游戲的結合。

完整代碼下載：Workflow

posted @ 2010-08-20 22:29 suyan010203 Views(4991) Comments(4) 收藏舉報

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試用Workflow開發WPF應用程序

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