Private Sub btnSMPT_Click(ByVal sender As System.Object, ByVal e As _
  System.EventArgs) Handles btnSMPT.Click
        Try
            ' Neue Mail generieren
            Dim mail As New Web.Mail.MailMessage
            mail.Subject = "Betreff-Test"
            mail.Body = "Hallo"
            Dim attachment As New Web.Mail.MailAttachment("C:\Test.pdf", _
              Web.Mail.MailEncoding.Base64)
            mail.Attachments.Add(attachment)
            ' Abprüfen, ob der Mailserver angegeben ist.
            Web.Mail.SmtpMail.SmtpServer = "exchange3"
            ' Absender eintragen.
            mail.From = "email@exchangebenutzer.de"
            ' Mailadresse angeben.
            mail.To = "xxx@web.de"
            ' Mail versenden.
            Web.Mail.SmtpMail.Send(mail)
 
        Catch ex As Exception
            MessageBox.Show(ex.ToString)
        End Try
    End Sub