private void buttongiris_Click(object sender, EventArgs e)
        {
            Veritabani.Connect();
            k1.USERNAME = textBoxad.Text;

            k1.SIFRE = textBoxsifre.Text;

            lk1 = Veritabani.KULLANICI_GETIR(k1);

            if (lk1.Count > 0 && textBoxad.Text != "" && textBoxad.Text != "")
            {
                ana.Show();
                this.Hide();
            }

            Veritabani.Disconnect();
        }