Dim mail As New System.Net.Mail.MailMessage
mail.From = New System.Net.Mail.MailAddress(txtFrom.Text)
mail.To.Add(txtTo.Text)
mail.Subject = txtSubject.Text
mail.Body = txtBody.Text
mail.IsBodyHtml = True
mail.Priority = System.Net.Mail.MailPriority.Normal
Dim smtp As New System.Net.Mail.SmtpClient
smtp.Host = "mail.tuserver.com"
'smtp.Credentials = New System.Net.NetworkCredential("usuario", "password")
Try
smtp.Send(mail)
txtBody.Text = "Mensaje enviado..."
Catch ex As Exception
txtBody.Text = "Error al enviar el correo" & vbCrLf & ex.Message
End Try