private void FillVehicles() { try { var districtId = -1; if (Session["UserdistrictId"] != null) { districtId = Convert.ToInt32(Session["UserdistrictId"].ToString()); } _fmsg.UserDistrictId = districtId; var ds = _fmsg.GetVehicleNumberPetroCardEdit(); if (ds == null) { throw new ArgumentNullException(nameof(ds)); } _helper.FillDropDownHelperMethodWithDataSet(ds, "VehicleNumber", "VehicleID", null, ddlVehicles); ddlVehicles.Enabled = false; } catch (Exception ex) { _helper.ErrorsEntry(ex); } }