public void verigoster()
        {
            Policeclass pc    = new Policeclass();
            DataTable   table = pc.goster();

            PoliceListe.DataSource = table;
        }
        private void btn_sil_Click(object sender, EventArgs e)
        {
            Policeclass pc = new Policeclass();

            pc.policesil(Convert.ToInt32(txt_id.Text));
            verigoster();
            temizle();
        }
        private void ben_guncelle_Click(object sender, EventArgs e)
        {
            Policeclass pc = new Policeclass();

            pc.policeguncelle(musterisec.SelectedValue.ToString(), sigortaturu.SelectedValue.ToString(), baslangic.Text, bitis.Text, Convert.ToInt32(fiyat.Text), Convert.ToInt32(txt_id.Text));
            verigoster();
            temizle();
        }