C# Winform close current form

Question

i have a current form that contain a grid. i create a function that open a new form when i double clic the row of this grid.

 public partial class Liste_Ordres : DevExpress.XtraEditors.XtraForm
    {
        public string Id = "";
        LeOrdre_BL oOrdre_BL = new LeOrdre_BL();
        LeOrdreStatut_Entite_BL oStatutOrdre_BL = new LeOrdreStatut_Entite_BL();

        public Liste_Ordres()
        {
           ....
        }

  private void Liste_DobleClic(object sender, EventArgs e)
        {
            try
            {
                Program.OrderId = gridView_Liste_Ordres.GetFocusedRowCellValue("NO_ORDRE").ToString();
                Program.StatusOrdre = Convert.ToInt32(gridView_Liste_Ordres.GetFocusedRowCellValue("STATUT_ORDRE"));
                if (gridView_Liste_Ordres.GetFocusedRowCellValue("MODAL_MODE").ToString() == "A")


                Fiche_Ordre f_Fiche = new          Fiche_Ordre(gridView_Liste_Ordres.GetFocusedRowCellValue("NO_ORDRE").ToString());
                f_Fiche.MdiParent = this.MdiParent;
                f_Fiche.Show();
            }
            catch (Exception excThrown)
            {
                MessageBox.Show(excThrown.Message);
            }
        }

how can i close Liste_Ordres ? when i put this.close(); it cannot work because of reference object is zero.

Answer 1

Declare you form object f_Fiche on class scope out side the Liste_DobleClic event to make it accessible to other method of the class.

 Fiche_Ordre f_Fiche = null;

private void Liste_DobleClic(object sender, EventArgs e)
{
        try
        {
            Program.OrderId = gridView_Liste_Ordres.GetFocusedRowCellValue("NO_ORDRE").ToString();
            Program.StatusOrdre = Convert.ToInt32(gridView_Liste_Ordres.GetFocusedRowCellValue("STATUT_ORDRE"));
            if (gridView_Liste_Ordres.GetFocusedRowCellValue("MODAL_MODE").ToString() == "A")


            f_Fiche = new          Fiche_Ordre(gridView_Liste_Ordres.GetFocusedRowCellValue("NO_ORDRE").ToString());
            f_Fiche.MdiParent = this.MdiParent;
            f_Fiche.Show();
        }
        catch (Exception excThrown)
        {
            MessageBox.Show(excThrown.Message);
        }
}