C#实现把String字符串转化为SQL语句中的In后接的参数

实现把string字符串转化为in后可用参数代码：

 public string stringtolist(string aa)
    {
        string bb1 = "(";
        if (!string.isnullorempty(aa.trim()))
        {
            
            string[] bb = aa.split(new string[] { "\r\n", ",", ";", "* " }, stringsplitoptions.removeemptyentries);
            for (int i = 0; i < bb.length; i++)
            {
                if (!bb1.contains(bb[i]))//去掉重复的輸入值
                {
                    bb1 += "'" + bb[i] + "',";
                }
            }
        }
        bb1 = bb1.substring(0, bb1.lastindexof(",")) + ")";
        return bb1;
    }