foreach (string item in Scanlist)
{
Storelist.Remove(item);
}

        List<string> wllist = new List<string>();
        string[] arr =Scanlist.ToArray(); //把扫描清单赋给数组          
        int scanqty = 0;
        string wl = string.Empty;
        string scanwl = string.Empty;
        foreach (var ir in arr.GroupBy(c => c))
        {//数组中找出重复的元素，并且计数
            wl = ir.Key.ToString();//元素
            scanqty = ir.Count();
            scanwl = wl.Substring(0, wl.LastIndexOf(";")).ToString();
            wllist.Add(scanwl+";件数:"+scanqty);
        }
        foreach (string rr in wllist)
        {
            string gwl = rr.Substring(0, rr.LastIndexOf(";")).ToString();
            string gqty = rr.Substring(rr.LastIndexOf(":") + 1).ToString();
            for (int k = 0; k < Storelist.Count; k++)
            {
                string item2 = Storelist[k].ToString();
                string storewl = item2.Substring(0, item2.LastIndexOf(";")).ToString();//编码
                string storeqty = item2.Substring(item2.LastIndexOf(":") + 1).ToString();//库存件数                   
                if (storewl.Equals(gwl) && !storeqty.Equals(gqty))
                {//物流编码相同，但件数不同，先移除再添加                                                  
                    Storelist.Remove(item2);
                    Storelist.Add(storewl + ";" + "件数:" + (int.Parse(storeqty) - int.Parse(gqty)));
                }
            } 
        }