Hi I hope that help you
MailMessage MailMesaji = new MailMessage();
MailMesaji.Subject = "Hello";
MailMesaji.Body = " How are u";
MailMesaji.BodyEncoding = Encoding.GetEncoding("Windows-1254");
MailMesaji.From = new MailAddress("Email Sender @ Domain");
MailMesaji.To.Add(new MailAddress("Email Reciever @ Domain"));
SmtpClient Smtp = new SmtpClient("smtp.mail.yahoo.com");
OpenFileDialog Ofd = new OpenFileDialog();
if (Ofd.ShowDialog() == DialogResult.OK)
{
string Att = Ofd.FileName;
Attachment ATTa = new Attachment(Att);
MailMesaji.Attachments.Add(ATTa);
}
Smtp.Credentials = new System.Net.NetworkCredential("Email Sender @ Domain", "PWD");
Smtp.Send(MailMesaji);
MessageBox.Show("mail Send");