這裡用的是網路上的伺服器來發送郵件的，並不是自己伺服器上的，例子中是Gmail的。

    private void SendEmail()

    {
         MailMessage objMailMessage;
         Attachment objMailAttachment;
         // 建立一個附件物件
         objMailAttachment = new Attachment("d://test.txt");//傳送郵件的附件
         // 建立郵件訊息
         objMailMessage = new MailMessage();
         objMailMessage.From = new MailAddress("

         objMailMessage.To.Add("[email protected]");//目的郵件地址俺的QQ郵箱

         objMailMessage.Subject = "郵件傳送標題：你好!";//傳送郵件的標題

         objMailMessage.Body = "郵件傳送標內容：測試一下是否傳送成功！";//傳送郵件的內容
         objMailMessage.IsBodyHtml = true;
         objMailMessage.BodyEncoding = System.Text.Encoding.UTF8;
         objMailMessage.Priority = System.Net.Mail.MailPriority.Normal;
         objMailMessage.Attachments.Add(objMailAttachment);//將附件附加到郵件訊息物件中
         //SMTP地址
         SmtpClient smtpClient = new SmtpClient("smtp.gmail.com");//網路上的代理伺服器
         smtpClient.EnableSsl = true;
         smtpClient.Credentials = new System.Net.NetworkCredential(objMailMessage.From.Address, "此處是郵箱的密碼");//設定發件人身份的資訊

         smtpClient.DeliveryMethod = System.Net.Mail.SmtpDeliveryMethod.Network;

         smtpClient.Host = "smtp." + objMailMessage.From.Host;

         smtpClient.Send(objMailMessage);
    }