Visual Basic

Imports System.Net.Mail
Class MainWindow
    Dim username As String
    Dim password As String
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.Windows.RoutedEventArgs) Handles Button1.Click

        Dim mail As New MailMessage
        mail.From = New MailAddress(txtFrom.Text)
        mail.To.Add(txtTo.Text)
        mail.Subject = txtSubject.Text
        mail.Body = txtMessage.Text
        Dim smtp As New SmtpClient("Smtp.gmail.com")
        smtp.EnableSsl = True
        smtp.Credentials = New System.Net.NetworkCredential(txtUsername.Text, PasswordBox1.Password)
        smtp.Port = 465
        smtp.Send(mail)
    End Sub
End Class