Receiving a list of all users

static ArrayList getUserList(string sign, string option, string low, string high)
        { 
 
            ERPConnect.LIC.SetLic("xxxxxxxxxxxxx");
 
            R3Connection con = new R3Connection("hamlet",
                                                11,
                                                "user",
                                                "passw",
                                                "DE",
                                                "800");            
 
            con.Open();            
 
            RFCFunction func = con.CreateFunction("BAPI_HELPVALUES_GET");
 
            func.Exports["OBJTYPE"].ParamValue = "USER";
            func.Exports["METHOD"].ParamValue = "GETDETAIL";
            func.Exports["PARAMETER"].ParamValue = "USERNAME";
 
            RFCStructure shlp = func.Exports["EXPLICIT_SHLP"].ToStructure();
            shlp["SHLPNAME"] = "USER_ADDR";
            shlp["SHLPTYPE"] = "SH";
 
            RFCStructure sfh = func.Tables["SELECTION_FOR_HELPVALUES"].AddRow(); ;
            sfh["SELECT_FLD"] = "MC_NAMELAS";
            sfh["SIGN"] = sign;
            sfh["OPTION"] = option;
            sfh["LOW"] = low;
            sfh["HIGH"] = high;
 
            func.Execute();
 
            con.Close();
 
            ArrayList user = new ArrayList();
            for (int i = 0; i < func.Tables["HELPVALUES"].RowCount; i++)
            {
                user.Add(func.Tables["HELPVALUES"].Rows[i, 0]);
            }
            if (user.Count == 0)
            {
                user.Add("No results matching criteria");
            }               
 
            return user;                           
        }

static void Main(string[] args)
        {
            ArrayList users = getUserList("I","CP","M*","");
            foreach (object userdetail in users)
            {
                Console.WriteLine(userdetail);
            }
            Console.ReadLine();
        }