UI線程塊

Question

我創建了一個簡單的WPF應用程序，並添加一個按鈕，默認的窗口。當我按一下按鈕，模擬較長的工作方法（使用Thread.sleep代碼（15000），模擬被調用。我試圖使按鈕異步然而，儘管下面網上的例子執行，一旦按鈕，整個窗鎖，我單擊並一直持續到下了Thread.Sleep（...）結束

任何想法，爲什麼發生這種情況

這裏是代碼：？

private void button1_Click(object sender, RoutedEventArgs e) 
{ 
    DoSomeAsyncWork(); 
} 

private void DoSomeAsyncWork() 
{ 
    System.Windows.Threading.Dispatcher.Run(); 
    Thread thread = new System.Threading.Thread(
     new System.Threading.ThreadStart(
      delegate() 
      { 
       Application.Current.Dispatcher.BeginInvoke(DispatcherPriority.Normal, new Action(() => Thread.Sleep(15000))); 
      } 
     )); 
    thread.Start(); 
} 

Answer 1

你把長運回UI線程。讓我來評論你的例子：

Thread thread = new System.Threading.Thread( 
    new System.Threading.ThreadStart( 
     delegate() { 
      // here we are in the background thread 

      Application.Current.Dispatcher.BeginInvoke(DispatcherPriority.Normal, 
       new Action(() => { 
        // here we are back in the UI thread 
        Thread.Sleep(15000); 
       })); 
     } 
    )); 

所以，你應該修改你這樣的例子：

Thread thread = new System.Threading.Thread( 
    new System.Threading.ThreadStart( 
     delegate() { 
      // here we are in the background thread 

      Thread.Sleep(15000); // <-- do the long operation here 

      Application.Current.Dispatcher.BeginInvoke(DispatcherPriority.Normal, 
       new Action(() => { 
        // here we are back in the UI thread 

        // do stuff here that needs to update the UI after the operation finished 
       })); 
     } 
    )); 

正如其他人所說，它更容易使用的BackgroundWorker類。這裏有一個例子：

private void DoSomeAsyncWork() 
{ 
    BackgroundWorker bw = new BackgroundWorker(); 

    bw.DoWork += (sender, args) => { 
     // do your lengthy stuff here -- this will happen in a separate thread 
     Thread.Sleep(15000); 
    } 

    bw.RunWorkerCompleted += (sender, args) => { 
     if (args.Error != null) // if an exception occurred during DoWork, 
      MessageBox.Show(args.Error.ToString()); // do your error handling here 

     // do any UI stuff after the long operation here 
     ... 
    } 

    bw.RunWorkerAsync(); // start the background worker 
} 

Answer 2

您應該使用BackgroundWorker的。

• http://msdn.microsoft.com/en-us/library/system.componentmodel.backgroundworker.aspx
• http://www.tanguay.info/web/index.php?pg=codeExamples&id=232

Answer 3

使用BeginInvoke你實際上是在執行UI線程上的代碼。

你只需要當你從後臺輔助線程更新UI使用此。如果你只是有：

Thread thread = new System.Threading.Thread(
    new System.Threading.ThreadStart(
     delegate() 
     { 
      Thread.Sleep(15000); 
     } 
    )); 

我認爲它會工作。

但是，你是不是養了「完成工作」事件，這樣你沒有的時候（或者實際上如果）線程完成得知。看看BackgroundWorker class。這爲你做了很多繁重的工作。您只需將代碼插入DoWork方法即可。