C# 代码优化！导致iis 频繁重启？

[fly_Apple10]

/// <summary>
    /// 绑定产品目录列表
    /// </summary>
    /// <param name="cid">公司ID</param>
    protected void BindBigProductCataLog(string cid)
    {
        Catagary ca = new Catagary();
        BllGlodMemberProductCatagorySort bllcatagory = new BllGlodMemberProductCatagorySort();
        ArrayList al = ca.GetOfferCatalogIDSort(cid);
        ArrayList al2 = bllcatagory.GetCatalogList(cid);
        if (al != null && al2 != null)
        {
            if (al.Count == al2.Count)
            {
                al = al2;
            }
        }
        DataTable dt = ca.GetAllProductCatalogChildSort(cid);
        DataTable dt2 = bllcatagory.GetChildCatalogList(cid);
        rptCatalogOne.DataSource = al;
        rptCatalogOne.DataBind();
        foreach (RepeaterItem rpone in rptCatalogOne.Items)
        {
            int i = rpone.ItemIndex;
            int cateGoryoneId;
            if (int.TryParse(al[i].ToString(), out cateGoryoneId))
            {
                DataTable listTwo = null;
                if (dt != null)
                {
                    listTwo = ca.GetChildCatalogListByParentIDSort(cateGoryoneId, dt);
                }
                DataTable listThree = null;
                if (dt2 != null)
                {
                    listThree = ca.GetChildCatalogListByParentIDSort(cateGoryoneId, dt2);
                }

                DataTable list_temp = null;
                if (listThree != null && listTwo != null)
                {
                    if (listTwo.Rows.Count == listThree.Rows.Count)
                    {
                        list_temp = listThree;
                    }
                    else
                    {
                        list_temp = listTwo;
                    }

                }
                else
                {
                    list_temp = listTwo;
                }
                Repeater rptCatalogTwo = (Repeater)rpone.FindControl("rptCatalogTwo");
                rptCatalogTwo.DataSource = list_temp;
                rptCatalogTwo.DataBind();

                //释放资源
                listTwo.Dispose();
                listTwo = null;
                listThree.Dispose();
                listThree = null;
                list_temp.Dispose();
                list_temp = null;

            }
        }
        //后面加上了释放资源
        dt.Dispose();
        dt = null;
        dt2.Dispose();
        dt2 = null;
    }

http://topic.csdn.net/u/20120413/15/25406b4b-4af8-451c-9cea-7fa65d0855de.html?seed=1619594395&r=78235842#r_78235842

以上代码如何优化？
为什么删我的贴，难道？？