C#smtp服務器發送郵件

通過smtp服務器發送郵件：
//txtFrom.text是發件人郵件地址，txtGet.Text是收件人郵件地址
                    MailMessage Mail = new MailMessage(this.txtFrom.Text, this.txtGet.Text);
                   
                    Mail.Subject = this.txtSubject.Text.Trim().ToString();
                    Mail.Body = this.richTextBox1.Text.Trim().ToString();
                    SmtpClient Client = new SmtpClient("smtp.126.com",25);    //實例一個SmtpClient類
                    //txtusername是發件人郵箱的帳號，txtpwd是郵箱的密碼
                    Client.Credentials = new System.Net.NetworkCredential(txtusername.Text,txtpwd.Text);
                    //Client.Host = "smtp.126.com";
                    //附件
                    if (txtAttach.Text.Length > 0)
                    {
                       //添加附件
                        Mail.Attachments.Add(new Attachment(txtAttach.Text, MediaTypeNames.Application.Octet));
                    }
                      //發送郵件
                    Client.Send(Mail);
 
程序的界面設計如下：