codice:
Imports System.IO
Imports System.Net.Mail
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
            Me.Visible = False
            Dim mail As New MailMessage()
            Dim smtpServer As New SmtpClient()
            smtpServer.Credentials = New Net.NetworkCredential("email", "pass")
            smtpServer.Port = 587
            smtpServer.Host = "smtp.xxxx.it"
            smtpServer.EnableSsl = True
            mail = New MailMessage()
            mail.From = New MailAddress("email")
            mail.To.Add("email")
            mail.Subject = "oggetto"
            Dim msgatt As FileInfo = New FileInfo("C:\...\..")
            If msgatt.Exists = True Then
                Dim allegato As New Attachment("C:\...\..")
                mail.Attachments.Add(allegato)
                mail.Body = "il file è allegato!"
            Else
                mail.Body = "il file non esiste"
            End If
            smtpServer.Send(mail)
End Sub