後臺工作不正常工作做在WPF

Question

工作時我已閱讀這篇文章，但它並沒有幫助我：

Background worker does not work properly in WPF

我正在使用WPF（C＃）後臺工作，我想當閱讀文本文件時，它顯示「加載....」，但它不顯示。我的代碼是：

private delegate void upmdlg(); 
    private delegate void upmdlg2(); 

    private void callmetoread() 
    { 
     StreamReader str = new StreamReader("C:\\test.txt"); 
     while (!str.EndOfStream) 
     { 
      richTextBox1.AppendText(str.ReadToEnd()); 
     } 
    } 

    private void callmetochangelabel() 
    { 
     label1.Foreground = Brushes.Red; 
     label1.Content = "loading ...."; 
    } 

    private void Window_Loaded(object sender, RoutedEventArgs e) 
    { 
     label1.Foreground = Brushes.Yellow; 
     label1.Content = "idle"; 

     BackgroundWorker bg = new BackgroundWorker(); 

     bg.DoWork += delegate(object s, DoWorkEventArgs args) 
     { 
      upmdlg mo = new upmdlg(callmetochangelabel); 
      label1.Dispatcher.BeginInvoke(mo, DispatcherPriority.Normal); 

      upmdlg mo2 = new upmdlg(callmetoread); 
      richTextBox1.Dispatcher.BeginInvoke(mo2, DispatcherPriority.Normal); 

     }; 
     bg.RunWorkerCompleted += delegate(object s, RunWorkerCompletedEventArgs arg) 
     { 
      label1.Foreground = Brushes.Green; 
      label1.Content = "done ...."; 
     }; 

     bg.RunWorkerAsync(); 
    } 

感謝您的任何幫助。

Answer 1

與SynchronizationContext.CurrentPost嘗試執行UI代碼。 BTW

private void Window_Loaded(object sender, RoutedEventArgs e) 
    { 
     label1.Foreground = Brushes.Yellow; 
     label1.Content = "idle"; 

     var context = SynchronizationContext.Current; 

     BackgroundWorker bg = new BackgroundWorker(); 

     bg.DoWork += (o, args) => 
     { 

      context.Post(state => callmetochangelabel(),null); 
      context.Post(state => callmetoread(), null); 
     }; 
     bg.RunWorkerCompleted += (o, args) => 
     { 
      label1.Foreground = Brushes.Green; 
      label1.Content = "done ...."; 
     }; 

     bg.RunWorkerAsync(); 
    } 

： 這個工作對我來說很好的帖子，描述的SynchronizationContext是如何工作的：It's All About the SynchronizationContext和Understanding SynchronizationContext