c# backgroundworker 无法处理我想要它执行的代码

Question

我的代码在强制执行时不会出现任何错误，我只是在尝试运行它时出现错误。它说 ThreadStateException 不受用户代码的控制，我在多个地方搜索了这个，我的所有代码看起来都以同样的方式工作，我知道问题是什么。这是不起作用的代码，

 private void button1_Click(object sender, EventArgs e)
 {
      backgroundWorker1.RunWorkerAsync();
 }

 private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
 {
      FolderBrowserDialog dlg2 = new FolderBrowserDialog();
      if (dlg2.ShowDialog() == DialogResult.OK)
      //do whatever with dlg.SelectedPath
      {
           DirectoryInfo source = new DirectoryInfo(dlg.SelectedPath);
           DirectoryInfo target = new DirectoryInfo(dlg2.SelectedPath);

           DirectoryInfo dir = new DirectoryInfo(dlg.SelectedPath);
           FileInfo[] fis = dir.GetFiles("*", SearchOption.AllDirectories);
           foreach (FileInfo fi in fis)
           {
                if (fi.LastWriteTime.Date == DateTime.Today.Date)
                {
                    File.Copy(fi.FullName, target.FullName +"\\"+ fi.Name, true);
                }
           }

      }
 }

任何帮助将不胜感激

Answer 1

您无法在线程中显示表单（对话框）。

 private void button1_Click(object sender, EventArgs e)
 {
     using (FolderBrowserDialog dlg2 = new FolderBrowserDialog())
     {
       if (dlg2.ShowDialog() == DialogResult.OK)           
       {
          backgroundWorker1.RunWorkerAsync(dlg2SelectedPath);
       }
    }
 }


private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
{
    string selectedpath = (string) e.Args;
    ....
}

另外，请确保处理 Completed 事件并检查 if (e.Error != null) ...
否则你将忽略错误。

Answer 2

在 DoWork 方法中添加一些异常处理。

请看这里： http:// /social.msdn.microsoft.com/Forums/en-US/Vsexpressvcs/thread/74d91404-9bc8-4f8f-8eab-4265afbcb101/

string ErrorMessage = "";
void bgw_DoWork(object sender, DoWorkEventArgs ea)
{
    //some variable declarations and initialization
    try
    {
        //do some odbc querying
        ErrorMessage = "";
    }
    catch (Exception ex)
    {
        //stuff..
        ErrorMessage = ex.Message;
    }
}

void bgw_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
{
    if (e.Error != null || !string.IsNullOrEmpty(ErrorMessage))
    {
        //do something
        MessageBox.Show(ErrorMessage);
    }
    else
    {
        //do something else
    }
}