Imports System.Net.Mail
Public Class Form1

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

    End Sub

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        'Start by creating a mail message object
        Dim MyMailMessage As New MailMessage()

        'From requires an instance of the MailAddress type
        MyMailMessage.From = New MailAddress("user@gmail.com")

        'To is a collection of MailAddress types
        MyMailMessage.To.Add("user@gmail.com")

        MyMailMessage.Subject = "GMail Test"
        MyMailMessage.Body = "This is the test text for Gmail email"

        'Create the SMTPClient object and specify the SMTP GMail server
        Dim SMTPServer As New SmtpClient("smtp.gmail.com")
        SMTPServer.Port = 587
        SMTPServer.Credentials = New System.Net.NetworkCredential("usuario@gmail.com", "password")
        SMTPServer.EnableSsl = True

        Try
            SMTPServer.Send(MyMailMessage)
            MessageBox.Show("Email Sent")
        Catch ex As SmtpException
            MessageBox.Show(ex.Message)
        End Try

    End Sub
End Class