//Add References

using System.Net;
using System.Net.Mail;

System.Net.Mail.SmtpClient client = new System.Net.Mail.SmtpClient();
System.Net.Mail.MailMessage msg = new System.Net.Mail.MailMessage();
msg.To.Add("xxx@gmail.com");
msg.From = new System.Net.Mail.MailAddress("xxx@gmail.com", "test Mail", System.Text.UTF8Encoding.UTF8);
msg.Subject = "test Mail";
msg.SubjectEncoding = System.Text.Encoding.UTF8;
string str = "< ttable>< ttr>< ttd> " + label1.Text + "< ttd>< ttd>" + textBox1.Text + "< ttd>"; //remove one t from <>
msg.Body =str;
msg.IsBodyHtml = true; // If Normal Data set it to false
msg.Priority = MailPriority.High;
//Adding Client Credentials
client.UseDefaultCredentials = true; // If Network Credentials
//client.Credentials = new System.Net.NetworkCredentials("xxx@gmail.com","passwordofgmail");
client.Port = 25; // 25 or 587
client.Host = "smtp.gmail.com";
client.EnableSsl = false;
object userState = msg;
client.Send(msg);