private void button1_Click(object sender, EventArgs e)
        {
            string To = this.textBox1.Text;//发送到
            string From = this.textBox2.Text;//发送邮箱
            string password = this.MaskedtextBox1.Text;//发送邮箱密码
            string name = this.textBox3.Text;
            if (To != "" & From != "")
            {
                SmtpClient smtp = new SmtpClient(); 
                smtp.DeliveryMethod = SmtpDeliveryMethod.Network; 
                smtp.EnableSsl = false;
                smtp.Host = "smtp.163.com";//格式：smtp.163.com
                smtp.Port = 25;            
                smtp.UseDefaultCredentials = true;
                
                smtp.Credentials = new NetworkCredential(From, password);
                MailMessage Message = new MailMessage();
                // Message.BodyEncoding = System.Text.Encoding.UTF8;
                Message.Priority = MailPriority.High;
                Message.From = new MailAddress(From, name, Encoding.GetEncoding(936));
               
                Message.ReplyTo = new MailAddress(From, "我的接收邮箱", Encoding.GetEncoding(936));
 Message.To.Add(ToAd);
                Message.Subject = textBox4.Text; //邮件标题
                Message.SubjectEncoding = Encoding.GetEncoding(936);
          
                Message.IsBodyHtml = true;
                Message.BodyEncoding = Encoding.GetEncoding(936);
                Message.Body = textBox5.Text;//内容
                if (textBox6.Text != "")
                {
                    Attachment att = new Attachment(@textBox6.Text);
                    Message.Attachments.Add(att);//加附件
                }

                try
                {
                    if (textBox6.Text != "")
                    {

                        EmailWithProgress();
                    }
                    smtp.Send(Message); //发送邮件，如果不返回异常， 则大功告成了。

                    MessageBox.Show("Email 已发送完成！", "系统V2.01");
                }
                catch (Exception ex)
                {
                    MessageBox.Show("发送失败！" + ex.ToString(), "系统V2.01");
                }

            }
        }
  public static int filelen = 0;
        private void EmailWithProgress()
        {
            string filepath = textBox6.Text;
            if (!File.Exists(filepath))
            {
                MessageBox.Show(filepath + "文件不存在", "系统V2.01");
                return;
            }
            else
            {

                FileInfo fi1elens = new FileInfo(filepath);
                int filelen = Convert.ToInt32(fi1elens.Length);



                progressBar1.Visible = true;//进度条
                progressBar1.Minimum = 1;
                progressBar1.Maximum = filelen;
                progressBar1.Value = 1;
                progressBar1.Step = 1;


                for (int x = 1; x <= filelen; x++)
                {
                    if (filelen > 0)
                    {
                        progressBar1.PerformStep();
                    }

                }

            }
        }
        private void button2_Click(object sender, EventArgs e)
        {
            Stream myStream = null;
            OpenFileDialog openFileDialog1 = new OpenFileDialog();

            openFileDialog1.InitialDirectory = "c:\\";
            openFileDialog1.Filter = "txt files (*.txt)|*.txt|All files (*.*)|*.*";
            openFileDialog1.FilterIndex = 2;
            openFileDialog1.RestoreDirectory = true;

            if (openFileDialog1.ShowDialog() == DialogResult.OK)
            {
                try
                {
                    if ((myStream = openFileDialog1.OpenFile()) != null)
                    {