How to check a checkboxList item on form load

This code doesnt work and i dont know why,
        foreach (ListItem li in cblRoles.Items)
        {
            foreach (DataRow row in dtUserCompanyRoles.Rows)
            {
                if (currentCompany == row[companyId].ToString()
                    && li.Value == row[roleId].ToString())
                {
                    li.Selected = true;
         &nb ...