Question

我有一个ListBox，我放了一些文件，如果文件不是AVI我自动转换它但我想当文件转换消息将写在标签上，文件现在转换为另一种格式，我怎么了现在只有在程序完成转换后才更新标签，而不是在过程中

完成所有修复后：

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

标签未更新，因为主UI线程忙于执行其他操作。

查看代码，您似乎在主UI线程中运行AVI文件转换业务。您应该在单独的线程中运行这个耗时的任务，以确保您的UI保持响应。

以下是对您的问题的解决方法，请将您的foreach (String file in listToRemove){}替换为：

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Thread代替Task（OP无法使用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...";});
}

将您的foreach (String file in listToRemove){}替换为：

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

Answer 2

将BackgroundWorker用于主要任务和调度程序以进行UI更新。

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

Dispatcher没有更新标签

2 个答案: