public void verigoster()
        {
            Sigortaclass sc    = new Sigortaclass();
            DataTable    table = sc.goster();

            SigortaListe.DataSource = table;
        }
        private void btn_sil_Click(object sender, EventArgs e)
        {
            Sigortaclass sc = new Sigortaclass();

            sc.sigortasil(Convert.ToInt32(txt_id.Text));
            verigoster();
            temizle();
        }
        private void ben_guncelle_Click(object sender, EventArgs e)
        {
            Sigortaclass sc = new Sigortaclass();

            sc.sigortaguncelle(txt_sigturu.Text, Convert.ToInt32(txt_id.Text));;
            verigoster();
            temizle();
        }
        private void btn_ekle_Click(object sender, EventArgs e)
        {
            Sigortaclass sc = new Sigortaclass();

            sc.sigortaekle(txt_sigturu.Text);
            verigoster();
            temizle();
        }