当将specifc类强制转换为其他对象时，JsonSerializer的行为与预期的不同 [英] JsonSerializer behaves not as expected when the specifc class is casted to something else

问题描述

我正在尝试从json.net迁移到Microsoft的json，发现某些行为有很大不同.

Im trying to migrate from json.net to microsoft's json and found something that behaves very differently.

让我们使用这个简化的示例:

Let's use this simplified example:

public interface IName
{
    string Name { get; set; }

}

public class Person : IName
{
    public string Name { get; set; }
    public int Age { get; set; }
}

public void Foo() 
{
   IName p = new Person {Age = 4, Name = "Waldo"};
   var s1 = System.Text.Json.JsonSerializer.Serialize(p); // --> {"Name":"Waldo"}
   var s2 = Newtonsoft.Json.JsonConvert.SerializeObject(p); // --> {"Name":"Waldo","Age":4}
}

Microsoft的序列化程序从IName序列化属性 JSON.NET序列化Person的属性

Microsoft's Serializers serializes properties from IName JSON.NET serializes properties from Person

是否有一种配置它的方式使其可以像JSON.NET一样工作?我可以通过的选项并不表示这是可配置的.我有事吗

Is there a way to configure it so that it would work like JSON.NET? The options that I could pass do not indicate that this is configurable. Did I overlook something?

推荐答案

这是因为序列化程序

This is because the serializer uses the type of the generic parameter, not the type of the passed value:

public static string Serialize<TValue>(TValue value, JsonSerializerOptions options = null)
{
    return WriteCoreString(value, typeof(TValue), options);
}

这会将typeof(IName)传递给WriteCoreString，并最终对该类型执行反射.

This passes typeof(IName) to WriteCoreString, and on that type ultimately reflection is performed.

您可以通过明确地将类型传递给接受该类型的重载来解决此问题:

You can work around this by explicitly passing the type to the overload that accepts that:

var s3 = System.Text.Json.JsonSerializer.Serialize(p, p.GetType());

这将返回:

{"Name":"Waldo","Age":4}

也可以使用object进行铸造，因为代码

Casting to object also works, as the code then calls value.GetType():

var s4 = System.Text.Json.JsonSerializer.Serialize((object)p);

这篇关于当将specifc类强制转换为其他对象时，JsonSerializer的行为与预期的不同的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！