c# - 如何等待线程完成运行？Thread.join 使我的主线程无响应？

Question

我正在开发使用 Windows 应用程序向多个用户发送邮件的项目，但是发生的事情是，当我使用 Thread.Join() 方法时，它使我的主 UI 无响应......我想要的是....我想在单独的线程上运行 SMTPClientTSeting() 方法，并希望我的主 UI 对其他工作保持响应。我想在后台运行此邮件发送活动...请建议我只使用线程概念。 ……

public void SendMail(dataset ds)
        {
                           for(inti=0<ds.Tables[0].Rows.Count<i++)
                            {

                                Thread tMail = new Thread(() => {
                                     resValue = SMTPClienTSetting(ds, mail);

                                });
                                tMail.IsBackground = true;
                                tMail.Start();
                                tMail.Join();
                                if (resValue == "True")
                                {
                                   Thread tPopUp = new Thread(new ThreadStart(this.ShowMessagePopUp));
                                   tPopUp.IsBackground = true;
                                  this.BeginInvoke((MethodInvoker)delegate{
                            });
                                   tPopUp.Start();
                                   lblPOpUpInfo = "Message sent successfully to \nAsset Owner : " + AssetOwner + "\n" + "Email : " + RecipientID;

                                }
                                else
                                {
                                     Thread tPopUp = new Thread(new ThreadStart(this.ShowMessagePopUp));
                                     tPopUp.IsBackground = true;
                                                                 this.BeginInvoke((MethodInvoker)delegate{
                            });
                                     tPopUp.Start();
                                     lblPOpUpInfo = "Message sending failed to \nAsset Owner :" + AssetOwner + "\n" + "Email : " + RecipientID + "!!!\nPlease check your SMTP details and\nInternet Connection..!!!";
                                }
                         }
        }
        #region Function for setting SMTP Client
                public string SMTPClienTSetting(DataSet ds, MailMessage MailstoSend)
                {
                    try
                    {
                        SmtpClient objsmtp = new SmtpClient();
                        NetworkCredential NetAccess = new NetworkCredential();

                        NetAccess.UserName = ds.Tables[0].Rows[0][0].ToString();
                        //NetAccess.Password = base64Decode(ds.Tables[0].Rows[0][1].ToString());

                        NetAccess.Password = genFunc.base64Decode(ds.Tables[0].Rows[0][1].ToString());
                        objsmtp.Credentials = NetAccess;

                        objsmtp.Host = ds.Tables[0].Rows[0][2].ToString();
                        objsmtp.Port = Convert.ToInt16(ds.Tables[0].Rows[0][3].ToString());

                        objsmtp.Send(MailstoSend);

                        //System.Threading.Thread.Sleep(500);

                        return "True";
                    }
                    catch (NullReferenceException nr)
                    {
                        return nr.Message;
                    }
                    catch (Exception ex)
                    {
                        return ex.Message;
                    }
                }
                #endregion
        }

    #region Function to show Pop Up window using separate thread
    public void ShowMessagePopUp()
    {
           try
            {
                frmHomePopUp homePopUp = new frmHomePopUp();
                mailTimer.Elapsed += delegate { mailTimer.Stop(); homePopUp.Close(); };
                //mailTimer.Elapsed += this.TimeEvent;
                mailTimer.Interval=5000;
                mailTimer.Enabled = true;
                homePopUp.lblInfo.Text = lblPOpUpInfo;
                homePopUp.Refresh();
                mailTimer.Start();
                homePopUp.ShowDialog();

            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }

    }
    #endregion

    public  void mailTimer_Elapsed(object source, EventArgs e)
    {
        //frmHome home;
        mailTimer.Stop();
      }

Answer 1

基本上：不要使用Thread.Join; 那就是阻塞。

一种适当的方法是在工作方法结束时执行任何 UI 工作：

Thread tMail = new Thread(() => {
     resValue = SMTPClienTSetting(ds, mail);

     if (resValue == "True") {
        // blah blah blah
     }
     // now: if you need to update any UI state:
     this.BeginInvoke((MethodInvoker)delegate {
        someControl.Text = lblPOpUpInfo; // for example
     });
});
tMail.IsBackground = true;
tMail.Start();

Invoke对/的调用BeginInvoke切换回 UI 线程，本质上是一个回调。

请注意，您可能还想使用ThreadPool而不是 a Threadhere。