调度没有及时更新标签

Question

我有一个列表框，我把一些文件，如果文件不是AVI我自动转换，但我希望在文件转换消息将这些文件现在转换到另一个标签上写格式，现在会发生什么，在我看来，只有当程序已完成将它们转换其更新标签，而不是在这个过程中

所有修补程序后：

private void btnAdd_Click(object sender, RoutedEventArgs e) 
{ 
    btnPlay.IsEnabled = false; 
    Stream checkStream = null; 
    Microsoft.Win32.OpenFileDialog openFileDialog = new Microsoft.Win32.OpenFileDialog(); 
    openFileDialog.Multiselect = true; 
    openFileDialog.InitialDirectory = "c:\\"; 
    openFileDialog.Filter = "All files (*.*)|*.*"; 
    openFileDialog.FilterIndex = 1; 
    openFileDialog.Title = "Please Select Source File"; 

    if ((bool)openFileDialog.ShowDialog()) 
    { 
     if ((checkStream = openFileDialog.OpenFile()) != null) 
     { 
      foreach (string file in openFileDialog.FileNames) 
      { 
       try 
       { 
        FileInfo fileInfo = new FileInfo(file); 
        listBoxFiles.Items.Add(file); 
       } 
       catch (Exception ex) 
       { 
        MessageBox.Show("Error: Could not read file from disk. Original error: " + ex.Message); 
       } 
      } 

      for (int i = 0; i < listBoxFiles.Items.Count; i++) 
      { 
       string path = (string)listBoxFiles.Items[i]; 
       FileInfo fileInfo = new FileInfo(path); 

       if (fileInfo.Extension != ".AVI") 
       { 
        listToRemove.Add(path); 
       } 
      } 

      (new System.Threading.Thread(ProcessAviFiles)).Start(); 

      foreach (string file in listToRemove) //remove all non .AVI files from listbox 
      { 
       listBoxFiles.Items.Remove(file); 
      } 
     } 
    } 
    else 
    { 

    } 

    if (listBoxFiles.Items.Count != 0) 
    { 
     btnClear.IsEnabled = true; 
     btnPlay.IsEnabled = true; 
    } 

    listToRemove.RemoveRange(0, listToRemove.Count); 

} 

功能：

public void ProcessAviFiles() 
{ 
    if (listToRemove.Count == 0) 
    { 
     return; 
    } 

    lblStatus2.Dispatcher.BeginInvoke(System.Windows.Threading.DispatcherPriority.Normal, new Action(() => { lblStatus2.Content = "Convert file to .AVI..."; })); 

    foreach (String file in listToRemove) 
    { 
     FileInfo fileInfo = new FileInfo(file); 
     editpcap = new EditCap(fileInfo); 
     String newFileName = editpcap._newFileName; 
     Dispatcher.BeginInvoke(System.Windows.Threading.DispatcherPriority.Normal, new Action(() => 
      { 
       listBoxFiles.Items.Add(editpcap._newFileName); 
      })); 
    } 

    lblStatus2.Dispatcher.BeginInvoke(System.Windows.Threading.DispatcherPriority.Normal, new Action(
     () => 
    { 
     lblStatus2.Content = "Select adapter and packet file, Click play button to start."; 
     btnClear.IsEnabled = true; 
    })); 
} 

Answer 1

标签没有更新，因为主UI线程忙于做其他事情。

展望你的代码，似乎你正在运行的主UI线程内的AVI文件转换业务。您应该在单独的线程中运行耗时的任务，以确保您的UI保持响应。

下面是一个修复您的问题，更换您的foreach (String file in listToRemove){}由：

Action aviConversion = new Action(() => { 
    if(listToRemove.Count == 0) return; // nothing to do 
    lblStatus2.Dispatcher.BeginInvoke(System.Windows.Threading.DispatcherPriority.Normal, 
           new Action(() => { lblStatus2.Content = "Convert file to .AVI...";}); 
     ); 
    foreach (String file in listToRemove){ 
     FileInfo fileInfo = new FileInfo(file); 
     editpcap = new (classes who convert the files)(fileInfo); 
     String newFileName = editpcap._newFileName; 
     Dispatcher.BeginInvoke(System.Windows.Threading.DispatcherPriority.Normal, 
           new Action(() => { 
           listBoxFiles.Items.Add(newFileName); 
     })); 
    } 
    lblStatus2.Dispatcher.BeginInvoke(System.Windows.Threading.DispatcherPriority.Normal, 
           new Action(() => { lblStatus2.Content = "AVI file conversion finished...";}); 
}); 
// Run this action in a separate thread... 
Task.Factory.StartNew(action, "beta"); 

编辑使用的Thread代替Task（OP不能使用Task）

private void ProcessAviFiles(){ 
     if(listToRemove.Count == 0) return; // nothing to do 
     lblStatus2.Dispatcher.BeginInvoke(System.Windows.Threading.DispatcherPriority.Normal, 
            new Action(() => { lblStatus2.Content = "Convert file to .AVI...";}); 
      ); 
     foreach (String file in listToRemove){ 
      FileInfo fileInfo = new FileInfo(file); 
      editpcap = new (classes who convert the files)(fileInfo); 
      String newFileName = editpcap._newFileName; 
      Dispatcher.BeginInvoke(System.Windows.Threading.DispatcherPriority.Normal, 
           new Action(() => { 
           listBoxFiles.Items.Add(newFileName); 
      })); 
     } 
     lblStatus2.Dispatcher.BeginInvoke(System.Windows.Threading.DispatcherPriority.Normal, 
            new Action(() => { lblStatus2.Content = "AVI file conversion finished...";}); 
} 

取代你foreach (String file in listToRemove){}由：

(new System.Threading.Thread(ProcessAviFiles)).Start(); 

Answer 2

使用的BackgroundWorker的主要任务和调度的UI更新。

backgroundWorker1.DoWork += worker_DoWork; 
backgroundWorker1.RunWorkerCompleted += worker_RunWorkerCompleted; 
backgroundWorker1.WorkerReportsProgress = true; 
backgroundWorker1.WorkerSupportsCancellation = true;   
backgroundWorker1.ProgressChanged +=new ProgressChangedEventHandler(backgroundWorker1_ProgressChanged);