将Windows Phone 7按钮的动作绑定到Expression Blend中的方法4

Question

我第一次尝试Windows Phone 7开发。我决定尝试从Expression Blend 4中的默认示例移植一个Silverlight Timer示例。完整Silverlight的定时器示例将TimerModel类绑定到定时器，启动/停止切换开关等。我已经想出了如何创建数据源/数据上下文并将属性绑定到屏幕上的东西。但是，Reset（）方法（它是一个void）不会显示在Windows Phone 7应用程序的可绑定选项中。它们都是完全相同的类，但由于某种原因，void方法不可绑定。有什么我需要启用的是完全的Silverlight应用程序，而不是Windows Phone 7？有什么特别的东西使得一个类的属性或方法在数据源时是可绑定的？这仅仅是Windows Phone 7的Silverlight功能子集的限制之一吗？

---

下面是这个类，它在两个应用程序中都是相同的。我想将按钮的点击绑定到Reset（）方法。

namespace Time 
{ 
    using System; 
    using System.ComponentModel; 
    using System.Windows.Threading; 
    using System.Windows.Data; 

    public class TimerModel : INotifyPropertyChanged 
    { 
     private bool isRunning; 
     private DispatcherTimer timer; 
     private TimeSpan time; 
     private DateTime lastTick; 

     public string FormattedTime 
     { 
      get 
      { 
       return string.Format("{0:#0}:{1:00}:{2:00.00}", this.time.Hours, this.time.Minutes, (this.time.Seconds + (this.time.Milliseconds/1000.0d))); 
      } 
     } 

     private void UpdateTimes() 
     { 
      this.NotifyPropertyChanged("FormattedTime"); 
      this.NotifyPropertyChanged("Hours"); 
      this.NotifyPropertyChanged("Minutes"); 
      this.NotifyPropertyChanged("Seconds"); 
     } 

     public bool Increment 
     { 
      get; 
      set; 
     } 

     public int Hours 
     { 
      get 
      { 
       return this.time.Hours; 
      } 
      set 
      { 
       this.time = this.time.Add(TimeSpan.FromHours(value - this.time.Hours)); 
       this.UpdateTimes(); 
      } 
     } 

     public int Minutes 
     { 
      get 
      { 
       return this.time.Minutes; 
      } 
      set 
      { 
       this.time = this.time.Add(TimeSpan.FromMinutes(value - this.time.Minutes)); 
       this.UpdateTimes(); 
      } 
     } 

     public int Seconds 
     { 
      get 
      { 
       return this.time.Seconds; 
      } 
      set 
      { 
       this.time = this.time.Add(TimeSpan.FromSeconds(value - this.time.Seconds)); 
       this.UpdateTimes(); 
      } 
     } 

     public bool IsRunning 
     { 
      get { return this.isRunning; } 
      set 
      { 
       if (this.isRunning != value) 
       { 
        this.isRunning = value; 
        if (this.isRunning) 
        { 
         this.StartTimer(); 
        } 
        else 
        { 
         this.StopTimer(); 
        } 
        this.NotifyPropertyChanged("IsRunning"); 
       } 
      } 
     } 

     private void StartTimer() 
     { 
      if (this.timer != null) 
      { 
       this.StopTimer(); 
      } 
      this.timer = new DispatcherTimer(); 
      this.timer.Interval = TimeSpan.FromMilliseconds(1); 
      this.timer.Tick += this.OnTimerTick; 
      this.lastTick = DateTime.Now; 
      this.timer.Start(); 
     } 

     private void StopTimer() 
     { 
      if (this.timer != null) 
      { 
       this.timer.Stop(); 
       this.timer = null; 
      } 
     } 

     private void OnTimerTick(object sender, EventArgs e) 
     { 
      DateTime now = DateTime.Now; 
      TimeSpan diff = now - this.lastTick; 
      this.lastTick = now; 

      if (this.Increment) 
      { 
       this.time = this.time.Add(diff); 
      } 
      else 
      { 
       this.time = this.time.Subtract(diff); 
      } 
      if (this.time.TotalMilliseconds <= 0) 
      { 
       this.time = TimeSpan.FromMilliseconds(0); 
       this.IsRunning = false; 
      } 
      this.UpdateTimes(); 
     } 

     public void Reset() 
     { 
      this.time = new TimeSpan(); 
      this.UpdateTimes(); 
     } 

     public TimerModel() 
     { 
     } 

     public event PropertyChangedEventHandler PropertyChanged; 

     private void NotifyPropertyChanged(string propertyName) 
     { 
      if (this.PropertyChanged != null) 
      { 
       this.PropertyChanged(this, new PropertyChangedEventArgs(propertyName)); 
      } 
     } 
    } 

}

Answer 1

我使用Caliburn Micro MVVM框架。它允许通过约定来绑定，所以如果你调用你的按钮RefreshButton，并且你的视图模型中有一个名为RefreshButton的方法，它将自动绑定到Click事件。非常强大和容易。

Answer 2

我发现Silverlight是使用股票CallMethodAction行动，这是不是在Windows Phone 7的可用看来，我有两个选择：

1. 使用的onClick像传统形式的事件，只需使用代码隐藏以编程方式调用该方法即可。
2. 创建我自己的自定义操作以重新创建CallMethodAction。 There is also an open source project which contains a port of the method from full-blown Silverlight, which you can find on Codeplex.