异常System.Reflection.TargetInvocationException - Backgroundworker

Question

我正在尝试使用backgroundworker(bgFileOpener)将openFileDialog打开的文件读入richTextBox(称为websiteInput_rtxt).

   private void bgFileOpener_DoWork(object sender, DoWorkEventArgs e)
    {
        try
        {
            foreach (var file in openFileDialog1.FileNames)
            {
                using (StreamReader sreader = new StreamReader(file))
                {

                    // while the stream reader didn't reach the end of the file - read the next line and report it
                    while (!sreader.EndOfStream)
                    {
                        if (bgFileOpener.CancellationPending)
                        {
                            e.Cancel = true;
                            return;
                        }

                        bgFileOpener.ReportProgress(0, sreader.ReadLine() + "\n");
                        Thread.Sleep(15);
                    }
                }
            }
        }
        catch (Exception) { }

    }

    private void bgFileOpener_ProgressChanged(object sender, ProgressChangedEventArgs e)
    {
            websiteInput_rtxt.AppendText(e.UserState.ToString());
    }

当表格在bgWorker仍在运行时关闭时,会抛出一个似乎没有被捕获的异常,有人可以告诉我缺少什么或可能导致异常的原因吗？

异常消息称为"System.Reflection.TargetInvocationException",而innerException则表示有关RichTextBox的内容.

Answer 1

关闭表单不会立即停止后台工作程序,这意味着您的ProgressChanged事件在关闭后仍然可以在表单上引发.

你可以解决这个问题:

private void bgFileOpener_ProgressChanged(object sender, ProgressChangedEventArgs e)
{
    if (this.IsDisposed) // Don't do this if we've been closed already
    {
        // Kill the bg work:
        bgFileOpener.CancelAsync();
    }
    else
        websiteInput_rtxt.AppendText(e.UserState.ToString());
}