Newtonsoft.Json.dll序列化為json，null值自動過濾

var jSetting = new JsonSerializerSettings {NullValueHandling = NullValueHandling.Ignore};
var json = JsonConvert.SerializeObject(response, Formatting.Indented, jSetting);

之前轉換的JSON為：

{"header":{"rspCode":"0000","rspDesc":"執行成功","rspErrorMsg":"","rspTime":"2014-03-05T13:40:48.7162196+08:00"},"body":{"order":{"orderid":"S0000001"},"product":null}}

加入代碼后轉換出來的為：

{"header":{"rspCode":"0000","rspDesc":"執行成功","rspErrorMsg":"","rspTime":"2014-03-05T13:40:48.7162196+08:00"},"body":{"order":{"orderid":"S0000001"}}}