jQuery Grid Plugin - jqGrid

My handler for select Dropdown and autocomplete:

public void ProcessRequest(HttpContext context)
        {
            context.Response.ContentType = "application/json";
            List<ListElement> colcommodityList = new List<ListElement>();
            DataTable dt = new DataTable();
            string html = string.Empty ;
            string key = context.Request.QueryString["sType"].ToString();
            switch (key)
            {
                case "com":
                    ListElement list;
                    dt = _Comm.GetDataTable();
                    if (dt != null && dt.Rows.Count > 0)
                    {
                        foreach (DataRow dr in dt.Rows)
                        {
                            list = new ListElement();
                            list.label = dr["CommodityName"].ToString();
                            list.value = Convert.ToInt32(dr["CommodityID"]);
                            colcommodityList.Add(list);
                            //lst.Add(dr["CommodityName"].ToString());
                        }
                    }
                    break;
                case "pkg":
                    html = html + "<select><option value=0></option>";
                    dt = _Gen.PackageTypeGetDataTable();
                    if (dt != null && dt.Rows.Count > 0)
                    {
                        foreach (DataRow dr in dt.Rows)
                        {
                            html = html + "<option value=" + Convert.ToInt32(dr["PackageTypeID"]) + ">" + dr["Description"].ToString()+ "</option>";
                        }
                        html = html + "</select>";
                        context.Response.Write(html);
                    }
                break;
            }
            JavaScriptSerializer js = new JavaScriptSerializer();
            string data = js.Serialize(colcommodityList);

            context.Response.Write(data);
        }