如何從另一個線程更新控件？

Question

我有一個簡單的WPF應用程序。我需要從另一個線程更新控件。 這是我的代碼

namespace WpfApplication1 
{ 
    class Stock 
    { 
     public int StockId { get; set; } 
     public string Name { get; set; } 
    } 

    class ThreadManager 
    { 
     public AddMoscowItem MoscowDelegate { get; set; } 
     public AddLondonItem LondonDelegate { get; set; } 
     public AddNewYorkItem NyDelegate { get; set; } 

     public ThreadManager() 
     { 
      InitStocks(); 
     } 

     private static readonly object lockObject = new object(); 

     private Stock[] stocks; 

     public ThreadManager(AddMoscowItem moscowDelegate, AddLondonItem londonDelegate, AddNewYorkItem nyDelegate) 
     { 
      MoscowDelegate = moscowDelegate; 
      LondonDelegate = londonDelegate; 
      NyDelegate = nyDelegate; 
     } 

     private void InitStocks() 
     { 
      if (stocks == null) 
       lock (lockObject) 
       { 
        if (stocks == null) 
         stocks = new Stock[] 
            { 
             new Stock() {Name = "Moscow", StockId = 1}, 
             new Stock() {Name = "London", StockId = 2}, 
             new Stock() {Name = "NY", StockId = 3} 
            }; 
       } 
     } 

     public void RunStocks() 
     { 
      //here we must call methods: AddMoscowListBoxItem, AddLondonListBoxItem 
      //how to do it linking to corresponding stock? 
     } 
    } 

    public delegate void AddMoscowItem(string msg); 
    public delegate void AddLondonItem(string msg); 
    public delegate void AddNewYorkItem(string msg); 

    /// <summary> 
    /// Interaction logic for MainWindow.xaml 
    /// </summary> 
    public partial class MainWindow : Window 
    { 
     private AddMoscowItem moscowDelegate; 
     private AddLondonItem londonDelegate; 
     private AddNewYorkItem nyDelegate; 

     public MainWindow() 
     { 
      InitializeComponent(); 

      moscowDelegate = AddMoscowListBoxItem; 
      londonDelegate = AddLondonListBoxItem; 
      nyDelegate = AddNYListBoxItem; 
      RunThreads(); 
     } 

     public void RunThreads() 
     { 
      ThreadManager stockThreads = new ThreadManager(moscowDelegate, londonDelegate, nyDelegate); 
      stockThreads.RunStocks(); 
     } 

     private void Window_Loaded(object sender, RoutedEventArgs e) 
     { 

     } 

     public void AddMoscowListBoxItem(string msg) 
     { 
      if (this.lbxMoscow.Dispatcher.Thread == Thread.CurrentThread) 
      { 
       lbxMoscow.Items.Add(msg); 
      } 
      else 
      { 
       lbxMoscow.Dispatcher.Invoke(DispatcherPriority.Background, new DispatcherOperationCallback(
              delegate { lbxMoscow.Items.Add(msg); 
                 return null; 
              }), null); 
      } 
     } 

     public void AddLondonListBoxItem(string msg) 
     { 
      if (this.lbxLondon.Dispatcher.Thread == Thread.CurrentThread) 
      { 
       lbxLondon.Items.Add(msg); 
      } 
      else 
      { 
       lbxLondon.Dispatcher.Invoke(DispatcherPriority.Background, new DispatcherOperationCallback(
              delegate 
              { 
               lbxLondon.Items.Add(msg); 
               return null; 
              }), null); 
      } 
     } 

     public void AddNYListBoxItem(string msg) 
     { 
      if (this.lbxNY.Dispatcher.Thread == Thread.CurrentThread) 
      { 
       lbxNY.Items.Add(msg); 
      } 
      else 
      { 
       lbxNY.Dispatcher.Invoke(DispatcherPriority.Background, new DispatcherOperationCallback(
              delegate 
              { 
               lbxNY.Items.Add(msg); 
               return null; 
              }), null); 
      } 
     } 
    } 
} 

任何建議都適合！

Answer 1

WPF控件具有線程親和力，所以你不能從另一個線程更新它們的狀態。您必須使用控件的Dispatcher將更新編組到UI線程。例如，要更新文本框：

textBox.Dispatcher.Dispatcher.Invoke(
     System.Windows.Threading.DispatcherPriority.Normal, 
     new Action(
     delegate() 
     { 
      textBox.Text = "Hello World"; 
     } 
    ));