ถามเรื่องการเขียนโปรแกรม ส่ง e-mail (เรื่องการ Config Sever)

Imports System.Net.Mail
Public Class Form1
   Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
      ' Set the caption bar text of the form.   
      Me.Text = "tutorialspoint.com"
   End Sub

   Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
      Try
          Dim Smtp_Server As New SmtpClient
          Dim e_mail As New MailMessage()
          Smtp_Server.UseDefaultCredentials = False
          Smtp_Server.Credentials = New Net.NetworkCredential("[email protected]", "password") ?
          Smtp_Server.Port = 587 ?
          Smtp_Server.EnableSsl = True
          Smtp_Server.Host = "smtp.gmail.com" ?

          e_mail = New MailMessage() 
          e_mail.From = New MailAddress() ?
          e_mail.To.Add("[email protected]")
          e_mail.Subject = "Email Sending"
          e_mail.IsBodyHtml = False
          e_mail.Body = "Test Email"
          Smtp_Server.Send(e_mail) 
          MsgBox("Mail Sent")

      Catch error_t As Exception
          MsgBox(error_t.ToString)
      End Try

   End Sub