private void PostPageChanges()
        {
            ProjectCostingSheetsNavigator projectCostingSheetsNavigator = new ProjectCostingSheetsNavigator(projectCostingSheetsNavigatorTDS);

            // Update grid rows
            foreach (GridViewRow row in grdCostingSheetsNavigator.Rows)
            {
                int costingSheetId = int.Parse(((Label)row.FindControl("lblCostingSheetID")).Text);
                bool selected = ((CheckBox)row.FindControl("cbxSelected")).Checked;

                projectCostingSheetsNavigator.Update(costingSheetId, selected);
            }

            projectCostingSheetsNavigator.Data.AcceptChanges();

            // Store datasets
            Session["projectCostingSheetsNavigatorTDS"] = projectCostingSheetsNavigatorTDS;
        }