C# 如何将 JSON.Net 中的 JObject 转换为 T
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How to cast JObject in JSON.Net to T
提问by Tracker1
I know that I can use JsonConvert.DeserializeObject<T>(string), however, I need to peek into the object's _type(which may not be the first parameter) in order to determine the specific class to cast to. Essentially, what I am wanting to do is something like:
我知道我可以使用JsonConvert.DeserializeObject<T>(string)，但是，我需要查看对象的_type（可能不是第一个参数）以确定要转换到的特定类。本质上，我想做的是：
//Generic JSON processor for an API Client.
function MyBaseType ProcessJson(string jsonText)
{
var obj = JObject.Parse(jsonText);
switch (obj.Property("_type").Value.ToString()) {
case "sometype":
return obj.RootValue<MyConcreteType>();
//NOTE: this doesn't work...
// return obj.Root.Value<MyConcreteType>();
...
}
}
...
// my usage...
var obj = ProcessJson(jsonText);
var instance = obj as MyConcreteType;
if (instance == null) throw new MyBaseError(obj);
采纳答案by yamen
First parse the JSON into a JObject. Then lookup the _typeattribute using LINQ to JSON. Then switch depending on the value and cast using ToObject<T>:
首先将 JSON 解析为 JObject。然后_type使用 LINQ to JSON查找属性。然后根据值切换并使用ToObject<T>：
var o = JObject.Parse(text);
var jsonType = (String)o["_type"];
switch(jsonType) {
case "something": return o.ToObject<Type>();
...
}
回答by JotaBe
JSON.NET has no direct ability to support both requisites:
JSON.NET 没有直接支持这两个必要条件的能力：
- custom name of the property holding the type name
- look for the property anywhere in the object
- 保存类型名称的属性的自定义名称
- 在对象的任何地方查找属性
The first requisites is fulfilled by JsonSubTypesThe second one by specifying thh right MetadataPropertyHandling
第一个要求由JsonSubTypes满足 第二个要求通过指定正确的MetadataPropertyHandling
