How to make an extension for JToken (Newtonsoft) in C#?

Question

I have some Web API that returns objects and collections, when deserialized I can get a JToken, which can be either a JObject or a JArray. I want to write an extension for the JToken type that will translate JToken to JObject or JArray.

I know that it is possible to make a parameter to select one of two types or to make two different methods, but I want to make one universal method for conversion.

How am I trying to implement such a task:

namespace App.Extensions
{
    public static class JsonExtensions
    {
        public static T To<T>(this JToken token) => (T)token;
    }
}

And getting an error:

Unable to convert type "Newtonsoft.Json.Linq.JToken" in "T".

Maybe there are more civil methods of solution?

Answer 1

i made you example to convert to class

void Main()
{
    string json = "{\"employees\":[{\"name\":\"Shyam\",\"email\":\"[email protected]\"},{\"name\":\"Bob\",\"email\":\"[email protected]\"},{\"name\":\"Jai\",\"email\":\"[email protected]\"}]}";
    var jobj = JsonConvert.DeserializeObject<JToken>(json);
    jobj.To<Root>().Dump();
}

public static class JsonExtensions
{
    public static T To<T>(this JToken token) where T : class
        => (T)token.ToObject(typeof(T));

}

public class Employee
{
    public string name { get; set; }
    public string email { get; set; }
}

public class Root
{
    public List<Employee> employees { get; set; }
}

if you need to work with Tokens - use JContainer

public static class JsonExtensions
{
    public static T To<T>(this JToken token) where T : JContainer 
        => (T)token.ToObject(typeof(T));

}

and call would be

jobj.To<JObject>().Dump();