Json转换空字符串而不是null

本文介绍了Json转换空字符串而不是null的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

我正在尝试序列化我的结构，以便未获得值的字符串获得其默认值"而不是null

I'm trying to serialize my struct so that the strings that didn't get a value get their default value "" instead of null

[JsonProperty(PropertyName = "myProperty", DefaultValueHandling = DefaultValueHandling.Populate)] [DefaultValue("")] public string MyProperty{ get; set; }

我在Json字符串中得到的结果:

My result in the Json string:

"myProperty": null,

我想要什么

"myProperty": "",

我还尝试创建一个没有任何影响的转换器，由于某些原因，甚至无法触发Convert和WriteJson函数:

I also tried creating a converter without any effect, the can Convert and WriteJson functions aren't even firing for some reason:

[JsonProperty(PropertyName = "myProperty")] [JsonConverter(typeof(NullToEmptyStringConverter))] public string MyProperty{ get; set; } class NullToEmptyStringConverter : JsonConverter { public override bool CanConvert(Type objectType) { return objectType == typeof(object[]); } public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer) { throw new NotImplementedException(); } public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer) { if (value == null) writer.WriteValue(""); } }

这不能帮助 Json.Net如何反序列化null为空字符串?

推荐答案

这应该有效:

var settings = new JsonSerializerSettings() { ContractResolver= new NullToEmptyStringResolver() }; var str = JsonConvert.SerializeObject(yourObj, settings);

public class NullToEmptyStringResolver : Newtonsoft.Json.Serialization.DefaultContractResolver { protected override IList<JsonProperty> CreateProperties(Type type, MemberSerialization memberSerialization) { return type.GetProperties() .Select(p=>{ var jp = base.CreateProperty(p, memberSerialization); jp.ValueProvider = new NullToEmptyStringValueProvider(p); return jp; }).ToList(); } } public class NullToEmptyStringValueProvider : IValueProvider { PropertyInfo _MemberInfo; public NullToEmptyStringValueProvider(PropertyInfo memberInfo) { _MemberInfo = memberInfo; } public object GetValue(object target) { object result = _MemberInfo.GetValue(target); if (_MemberInfo.PropertyType == typeof(string) && result == null) result = ""; return result; } public void SetValue(object target, object value) { _MemberInfo.SetValue(target, value); } }