C#把json对象序列（List<T>）转化为字符串时去掉值为null的字段

listData为序列，如下所示：

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

 如果不想生成的json字符串带有缩进格式符号\r\n则要使用如下方法：

 var jsonSetting = new JsonSerializerSettings { NullValueHandling = NullValueHandling.Ignore,Formatting=Formatting.None };
 insertInfo.GoodsDetailsStrJson = JsonConvert.SerializeObject(listData, jsonSetting);