c# - WPF:使用匿名方法的 UnauthorizedAccessException

Question

事情是这样的，我想创建一个简单的应用程序，从一个站点复制许多文件，然后将它们移动到另一个站点；但使用异步方法并创建一个新线程。

private void button3_Click(object sender, RoutedEventArgs e)
{

    //progressBar1.Maximum = _FileInfoArray.Count;

    DispatcherTimer dt1 = new DispatcherTimer();
    foreach (FileInfo Fi in _FileInfoArray)
    {
        Thread t = new Thread(new ThreadStart(delegate()
        {
            DispatcherOperation _dispOp = progressBar1.Dispatcher.BeginInvoke(DispatcherPriority.Loaded, new Action(delegate()
            {

                File.Copy(txtdestino.Text, Fi.FullName, true);

                //progressBar1.Value = n;
                //txtstatus.Content = ("Copiados " + n.ToString() + " archivos");
                //Thread.Sleep(100);
            }
            ));
            _dispOp.Completed += new EventHandler(_dispOp_Completed);
        }
            ));
        t.Start();
    }
}

UnauthorizedAccessException 被抛出!它说我无法访问 txtdestino 内容。一些线索？

-------------------------------------------- ------------------------------编辑这是包含所有更改的版本，得到相同的错误 :( 任何线索？

private void button4_Click(object sender, RoutedEventArgs e)
{
    //First: Build mynames
    List<string> mynames = new List<string>();
    foreach (FileInfo fi in _FileInfoArray)
    {
        mynames.Add(fi.FullName);
    }



    Thread t = new Thread(new ThreadStart(delegate()
       {
          foreach (string fullname in mynames)
            {
            DispatcherOperation _dispOp = progressBar1.Dispatcher.BeginInvoke(DispatcherPriority.Loaded, new Action(delegate()
            {
                string destino = System.IO.Path.Combine(@"C:\", System.IO.Path.GetFileName(fullname));
                File.Copy(fullname, destino, true);
                //Some progressbar changes
            }
            ));
            _dispOp.Completed += new EventHandler(_dispOp_Completed);
          }
        }
                ));
        t.Start();
    }

---

File.Copy(txtdestino.Text, Fi.FullName, true);//这里抛出异常

Answer 1

对 UI 元素的调用必须在 UI 线程中完成。尝试在循环之前获取文本值。

string txt = txtdestino.Text;
foreach (FileInfo Fi in _FileInfoArray)
{
    ....
    File.Copy(txt, Fi.FullName, true);