"abc,def,ccc,ddd;qwe,rty;cccc;"以分号为间隔，再以逗号为间隔，取第一个

string str1 = "abc,def,ccc,ddd;qwe,rty;cccc;";
        string[] str2 = str1.Split(';');
        //Response.Write(str2.Length);
        //Response.Write(str2[2].ToString());
        foreach (string s in str2)
        {
            string[] singleStr = s.Split(',');
            Response.Write(singleStr[0] + "<br />");
        }