Unity Json cannot serialize a generic list

Question

I am attempting to write a method that takes in an object and will use the Unity JsonUtility or the JsonHelper and returns the serialized version of that object. When I run the below debugging code everything works correctly.

    object t = new List<Player>
    {
        new Player
        {
            Name = "asdf",
            ID = Guid.NewGuid().ToString()
        }
    };

    if (t is IEnumerable<Player> list)
        Debug.Log(JsonHelper.ToJson(list.ToArray()));

//Result {"Items":[{"ID":"eff6ca08-b464-4e57-9f2e-f49a0cb869ff","Name":"asdf"}]}

However, my actual method does not return the same thing.

 public void SeriailizeObject<T>(T obj)
 {
    if (obj is IEnumerable<T> list)
    {
        Debug.Log(JsonHelper.ToJson(list.ToArray()));
        //Result {}
    }
    ...

Does anyone know if you can serialize a generic list with Unity's JsonUtility?

@JohnathanBarclay can you expand on that? When I debug the method, I do enter the if statement. — Travis Pettry, Mar 25 '20 at 10:50
It would cause an infinitely recursive structure. Think about it, if `T` is `IEnumerable` what is `T`? — Johnathan Barclay, Mar 25 '20 at 10:54

score 0 · Answer 1 · answered Mar 25 '20 at 11:02

When calling SeriailizeObject(new List<Player>()), typeof(T) is equal to List<Player> and obj is not an IEnumerable<List<Player>>.

When calling SeriailizeObject(t), typeof(T) is equal to object and obj is an IEnumerable<object> (assuming that t is a List<Player>).

Unity Json cannot serialize a generic list

1 Answers1