private void btn_SiparisEkle_Click(object sender, EventArgs e)
 {
     if (MusteriId != 0)
     {
         Form_Siparis siparis = new Form_Siparis(MusteriId);
         siparis.ShowDialog();
     }
     else
     {
         MessageBox.Show("Müşteri seçin !", "Uyarı", MessageBoxButtons.OK, MessageBoxIcon.Warning);
     }
 }
        private void dg_Siparisler_DoubleClick(object sender, EventArgs e)
        {
            Form_Siparis siparis = new Form_Siparis(true, SiparisId);

            siparis.ShowDialog();
        }