private void bindTreeView(RadTreeView rtrDepartment)
        {
            // ---- BIND DU LIEU VAO LISTVIEW --
            cls_DepartmentInformation dInfor = new cls_DepartmentInformation();
            dInfor.CompanyId = Convert.ToInt16(ddlBelongCompany.SelectedValue);
            DataTable dtDepart = dInfor.SelectByComId();
            ViewState["DT_DEPARTMENT"] = dtDepart;

            RadTreeNode node = new RadTreeNode();
            node.Text = "--- Lựa chọn ---";
            node.Value = "0";

            rtrDepartment.Nodes.Add(node);
            addNodeTreeView("0", node, dtDepart);
        }