asp.net send mail without a third party oh ~~~~__.net

First, you introduce a using System.Web.Mail namespace

The main code is as follows:

String Sreturn = String. Empty;
MailMessage MAILMSG = new MailMessage ();
Mailmsg.bodyformat = mailformat.html;
mailmsg.to = "ch@yahoo.com.cn";
Mailmsg.from = "ch@sohu.com";
Mailmsg.subject = "This is the old I sent you the mail, please answer ~";
Mailmsg.body = "This is the content ah." ";

MAILMSG.FIELDS.ADD ("Http://schemas.microsoft.com/cdo/configuration/smtpauthenticate", "1");
MAILMSG.FIELDS.ADD ("Http://schemas.microsoft.com/cdo/configuration/sendusername", "Here is the sender's mailbox");
MAILMSG.FIELDS.ADD ("Http://schemas.microsoft.com/cdo/configuration/sendpassword", "Here is the password");
//
Smtpmail.smtpserver = "smtp.sohu.com";//smpt server
Try
{

    smtpmail.send (MAILMSG);
    this. Label1.Text = "Send Success";
   }
   catch (Exception err)
   {
    this. Label2.Text = "<font color=red> send failed" + Err. Message.tostring () + "</font>";
   }