检查URL参数是否合法

 string combinationID = Request.QueryString["CombinationID"];
        string buyingPriceListID = Request.QueryString["PriceListID"];
        if (combinationID != null && CommonFunction.IsInt(combinationID) && combinationID.Length < int.MaxValue.ToString().Length)
        {
            m_CombinationID = int.Parse(combinationID.ToString());
        }
        if (buyingPriceListID != null && CommonFunction.IsInt(buyingPriceListID) && buyingPriceListID.Length < int.MaxValue.ToString().Length)
        {
            m_BuyingPriceListID = int.Parse(buyingPriceListID.ToString());
        }

public static bool IsInt(string input)
        {
            return Regex.IsMatch(input, @"^\d+$");
        }

string script = "<script type='text/javascript'>alert('{0}');window.location.href='BuyingPriceList.aspx';</script>";
        if (this.m_CombinationID == 0 || !entityCombination.ObjectExist)
        {
            script = string.Format(script, this.getMessage("M10022"));
            Response.Write(script);
            Response.End();
        }
        if (this.m_BuyingPriceListID == 0 || !entityBPList.ObjectExist)
        {
            script = string.Format(script, this.getMessage("M10023"));
            Response.Write(script);
            Response.End();
        }