将JSON字符串反序列化为类 [英] Deserialize JSON string into class with reflection

问题描述

我试图将一个JSON字符串反序列化成一个自定义类。我必须使用反射。我有一个字典，我序列化，发送到一个HttpPut方法，反序列化JSON字符串，并阅读字典字段。这是我到目前为止：

我把值放入字典中，像这样：

 字典< string，object> valuesToUpdate = new Dictionary< string，object>（）; 
 Person p = new Person（）; 
 p.personName =OrigName; 
 p.age =25; 
 p.isAlive = true; 
 valuesToUpdate.Add（Person，p）; 
 valuesToUpdate.Add（Length，64.0）; 
  

我使用JSON来序列化它：

  string jsonString = JsonConvert.SerializeObject（valuesToUpdate）; 
  

然后我接受jsonString并将其发送到REST API PUT方法。 PUT方法基于字典中的Key值使用反射来更新自定义对象上的各种变量（在此示例中，我将更新customObject.Person和customObject.Length）。

PUT调用反序列化jsonString，如下所示：

  string，object> newFields = JsonConvert.DeserializeObject< Dictionary< string，object>>（jsonString）; 
 

我遍历newFields并想使用反射来更新customObject的Person类。这是我的HttpPut方法读取jsonString：

  [HttpPut（/ test / stuff）] 
 public string PutContact（[FromBody] dynamic jsonString）
 {
字典< string，object> newFields = JsonConvert.DeserializeObject< Dictionary< string，object>>（jsonString）; 
 foreach（newFields中的var字段）
 {
 Console.WriteLine（\\\
Field key：+ field.Key）; 
 Console.WriteLine（Field value：+ field.Value +\\\
）; 
 
 PropertyInfo propInfo = typeof（Contact）.GetProperty（field.Key）; 
类型propertyType = propInfo.PropertyType; 
 var value = propInfo.GetValue（contactToUpdate，null）; 
 
 if（propertyType.IsClass）
 {
 propInfo.SetValue（contactToUpdate，field.Value，null）; 
} 
} 
} 
  

/ p>



类型为Newtonsoft.Json.Linq.JObject的对象不能转换为类型'Person';

我也尝试使用JSON的PopulateObject方法，但它返回了这个错误：

Newtonsoft.Json.JsonSerializationException：无法将JSON对象填充到类型Person上。路径'personName'，第1行....

基本上，如何获取JSON字符串，一个类（在我的例子中是'Person'类），并用反射设置它到customObject的Person字段？

解决方案

> if（propertyType.IsClass）
{
propInfo.SetValue（contactToUpdate，（（JObject）field.Value）.ToObject（propertyType），null）;
}





I'm trying to deserialize a JSON string into a custom class. I have to use reflection. I have a dictionary that I serialize, send over to an HttpPut method, deserialize the JSON string, and read the dictionary fields. Here's what I have so far:

I'm putting values into the Dictionary like this:

Dictionary<string, object> valuesToUpdate = new Dictionary<string, object>();
Person p = new Person();
p.personName = "OrigName";
p.age = "25";
p.isAlive = true;
valuesToUpdate.Add("Person", p);
valuesToUpdate.Add("Length", 64.0);

I'm using JSON to serialize it like this:

string jsonString = JsonConvert.SerializeObject(valuesToUpdate);

I then take the jsonString and send it over to a REST API PUT method. The PUT method updates various variables on a custom object based on the Key values in the dictionary using reflection (In this example I'm updating customObject.Person and customObject.Length).

The PUT call deserializes the jsonString like this:

Dictionary<string, object> newFields = JsonConvert.DeserializeObject<Dictionary<string, object>>(jsonString);

I iterate through newFields and want to use reflection to update customObject's "Person" class. This is my HttpPut method that reads the jsonString:

[HttpPut("/test/stuff")]
public string PutContact([FromBody]dynamic jsonString)
{
    Dictionary<string, object> newFields = JsonConvert.DeserializeObject<Dictionary<string, object>>(jsonString);
    foreach (var field in newFields)
    {
        Console.WriteLine("\nField key: " + field.Key);
        Console.WriteLine("Field value: " + field.Value + "\n");

        PropertyInfo propInfo = typeof(Contact).GetProperty(field.Key);
        Type propertyType = propInfo.PropertyType;
        var value = propInfo.GetValue(contactToUpdate, null);

        if (propertyType.IsClass)
        {
            propInfo.SetValue(contactToUpdate, field.Value, null);
        }
    }
}

This generates the error:

Object of type Newtonsoft.Json.Linq.JObject' cannot be converted to type 'Person';

I've also tried using JSON's PopulateObject method but it returned this error:

Newtonsoft.Json.JsonSerializationException: Cannot populate JSON object onto type 'Person'. Path 'personName', line 1....

So basically, how can you go about taking a JSON string, converting it to a class (in my case the 'Person' class), and setting it to customObject's Person field with reflection?

解决方案

if (propertyType.IsClass)
{
    propInfo.SetValue(contactToUpdate, ((JObject)field.Value).ToObject(propertyType), null);
}

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