private void button1_Click(object sender, EventArgs e)
        {
            //發信人和收信人以及內容
            MailMessage msg = new MailMessage();
            msg.Body = this.richTextBox1.Text;
            msg.Subject = this.textBox2.Text;
            msg.From = new MailAddress("[email protected]");
            msg.To.Add(this.textBox1.Text);//傳送到哪兒
            msg.IsBodyHtml = true;
            msg.Attachments.Add(new Attachment(textBox3.Text));


            //伺服器
            SmtpClient client = new SmtpClient();
            client.Host = "smtp.163.com";//發件方伺服器地址
            client.Port = 25;//可以省略 埠


            //證書的設定
            NetworkCredential credential = new NetworkCredential();
            credential.UserName = "anxin591025";
            credential.Password = "";


            client.Credentials = credential;
            client.Send(msg);
        }


        private void button2_Click(object sender, EventArgs e)
        {
            OpenFileDialog op = new OpenFileDialog();
            //op.ShowDialog();
            if(System.Windows.Forms.DialogResult.OK==op.ShowDialog())
            textBox3.Text = op.FileName;
        }