如何添加“未定义"到JObject集合-JToken/JValue.Undefined在哪里? [英] How to add "undefined" to a JObject collection - where is JToken/JValue.Undefined?

问题描述

使用Json.NET时，我尝试使用动态创建JSON结构. JSON到LINQ" 支持.

When using Json.NET, I am trying to create a JSON structure dynamically using the "JSON to LINQ" support.

在下面，jObject是 JObject 和JObject .Add需要(字符串， JToken ).但是，我找不到如何添加未定义或Null令牌的方法，也无法找到如何使用适当的Null/Undefined类型创建JValues.

In the following, jObject is a JObject and JObject.Add takes (string, JToken). However, I cannot find out how to add either an Undefined or a Null token - nor can I find out how to create JValues with the appropriate Null/Undefined type.

string value = GetValue();
if (value == "undefined") {
  jObject.Add(key, /* how to add "Undefined" token? */);
} else if (value == "null") {
  jObject.Add(key, /* how to add "Null" token? */);
} else {
  jObject.Add(key, new JToken(value));  /* String value/token */
}

如何为JSON未定义显式添加JToken/JValue? JSON Null怎么样?

How do I explicitly add a JToken/JValue for a JSON Undefined? How about for a JSON Null?

推荐答案

将属性设置为 undefined 在功能上等同于完全不设置该属性.因此，如果属性未定义，则只需不向JObject添加任何属性. (这可能就是JSON不支持undefined的原因-它是完全多余的.)

Setting a property to undefined is functionally equivalent to not setting the property at all. So, if the property is undefined, you just don't add any properties to your JObject. (And this is probably the reason why undefined isn't supported by JSON — it's completely redundant.)

空用new JValue((object)null)表示.

P.S.使用代码，您将无法分辨字符串"undefined"和undefined值之间以及"null"和null之间的区别.您可能需要重新考虑您的设计.

P.S. With your code, you won't be able to tell the difference between a string "undefined" and an undefined value, as well as between "null" and null. You probably need to rethink your design.

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