Cannot deserialize the current JSON object (e.g. {"name":"value"}) into type 'Value[]' because the type requires a JSON array (e.g. [1,2,3])

Question

I'm struggling with this exception. I'm trying to get some info from a json file and get some C# object out of it. But for some reasons, Unity does not allow me to deserialize it.

Here's my C# code:

IEnumerator SendRequest(string urlParam, Action<UnityWebRequest> callback)
    {
        using (webRequest = UnityWebRequest.Get(urlParam))
        {
            yield return webRequest.SendWebRequest();
            callback(webRequest);

            if (webRequest.isNetworkError || webRequest.isHttpError)
                Debug.LogError(webRequest.error);
            //else Debug.Log("Command has been performed successfully");
        }
    }

public void StartTestSuite2()
    {
        StartCoroutine(SendRequest("http://localhost:8086/down|PopOut1", (UnityWebRequest req) =>
        {
            if (req.isNetworkError || req.isHttpError)
            {
                Debug.Log($"{req.error}: {req.downloadHandler.text}");
            }
            else
            {
                Value[] values = JsonConvert.DeserializeObject<Value[]>(req.downloadHandler.text);

                foreach (Value value in values)
                {
                    Debug.Log(value.x);
                }
            }
        }));
    }

I've already googled it and found some people having the same issue but I can't figure out how to fix my problem here. I've tried deserializing Value instead of Value[], and it does work actually.

But then I cannot go through my table with a foreach (which I need)

Can anyone help me please ? Thanks,

EDIT : Here's my "Value" types:

public class Value
{
    public string name;
    public string type;
    public float x;
    public float y;
    public int instanceID;
}

And here's my json file:

{
    "scene": "UI",
    "gameObjectDefinitions": [{
        "name": "Image",
        "type": "UnityEngine.RectTransform",
        "x": 314.79595947265627,
        "y": 327.6845397949219,
        "instanceID": 28548,
        "buttons": [],
        "children": []
    }, {
        "name": "TopFade",
        "type": "UnityEngine.RectTransform",
        "x": 26.790924072265626,
        "y": 326.97796630859377,
        "instanceID": 28614,
        "buttons": ["TopFade (UnityEngine.UI.Button)"],
        "children": [{
            "name": "Text",
            "type": "UnityEngine.RectTransform",
            "x": 26.790924072265626,
            "y": 326.97796630859377,
            "instanceID": 28342,
            "buttons": [],
            "children": []
        }]
    }, {
        "name": "Button (1)",
        "type": "UnityEngine.RectTransform",
        "x": 81.19093322753906,
        "y": 327.207763671875,
        "instanceID": 28600,
        "buttons": ["Button (1) (UnityEngine.UI.Button)"],
        "children": [{
            "name": "Text",
            "type": "UnityEngine.RectTransform",
            "x": 81.19093322753906,
            "y": 327.207763671875,
            "instanceID": 28792,
            "buttons": [],
            "children": []
        }]
    }, {
        "name": "Button (2)",
        "type": "UnityEngine.RectTransform",
        "x": 135.5909423828125,
        "y": 327.207763671875,
        "instanceID": 28506,
        "buttons": ["Button (2) (UnityEngine.UI.Button)"],
        "children": [{
            "name": "Text",
            "type": "UnityEngine.RectTransform",
            "x": 135.5909423828125,
            "y": 327.207763671875,
            "instanceID": 28576,
            "buttons": [],
            "children": []
        }]
    }, {
        "name": "Button (3)",
        "type": "UnityEngine.RectTransform",
        "x": 602.7999877929688,
        "y": 327.207763671875,
        "instanceID": 28628,
        "buttons": ["Button (3) (UnityEngine.UI.Button)"],
        "children": [{
            "name": "Text",
            "type": "UnityEngine.RectTransform",
            "x": 602.7999877929688,
            "y": 327.207763671875,
            "instanceID": 28450,
            "buttons": [],
            "children": []
        }]
    }, {
        "name": "Button (4)",
        "type": "UnityEngine.RectTransform",
        "x": 548.4000244140625,
        "y": 327.207763671875,
        "instanceID": 28520,
        "buttons": ["Button (4) (UnityEngine.UI.Button)"],
        "children": [{
            "name": "Text",
            "type": "UnityEngine.RectTransform",
            "x": 548.4000244140625,
            "y": 327.207763671875,
            "instanceID": 28540,
            "buttons": [],
            "children": []
        }]
    }, {
        "name": "Button1Panel",
        "type": "UnityEngine.RectTransform",
        "x": 26.808990478515626,
        "y": 287.9584045410156,
        "instanceID": 28724,
        "buttons": [],
        "children": [{
            "name": "Text",
            "type": "UnityEngine.RectTransform",
            "x": 26.808990478515626,
            "y": 287.9584045410156,
            "instanceID": 28662,
            "buttons": [],
            "children": []
        }]
    }, {
        "name": "Button2Panel",
        "type": "UnityEngine.RectTransform",
        "x": 81.17160034179688,
        "y": 287.9584045410156,
        "instanceID": 28742,
        "buttons": [],
        "children": [{
            "name": "Text (1)",
            "type": "UnityEngine.RectTransform",
            "x": 81.17160034179688,
            "y": 287.9584045410156,
            "instanceID": 28372,
            "buttons": [],
            "children": []
        }]
    }, {
        "name": "Button3Panel",
        "type": "UnityEngine.RectTransform",
        "x": 135.55799865722657,
        "y": 287.9584045410156,
        "instanceID": 28332,
        "buttons": [],
        "children": [{
            "name": "Text (2)",
            "type": "UnityEngine.RectTransform",
            "x": 135.55799865722657,
            "y": 287.9584045410156,
            "instanceID": 28476,
            "buttons": [],
            "children": []
        }]
    }, {
        "name": "PopOutMaster",
        "type": "UnityEngine.RectTransform",
        "x": 835.2000122070313,
        "y": 198.75999450683595,
        "instanceID": 28776,
        "buttons": [],
        "children": [{
            "name": "PopOut1",
            "type": "UnityEngine.RectTransform",
            "x": 684.739990234375,
            "y": 198.75999450683595,
            "instanceID": 28310,
            "buttons": ["PopOut1 (UnityEngine.UI.Button)"],
            "children": [{
                "name": "Text",
                "type": "UnityEngine.RectTransform",
                "x": 583.5560302734375,
                "y": 198.75999450683595,
                "instanceID": 28784,
                "buttons": [],
                "children": []
            }]
        }]
    }, {
        "name": "PopOutMaster (1)",
        "type": "UnityEngine.RectTransform",
        "x": 835.2000122070313,
        "y": 135.52000427246095,
        "instanceID": 28834,
        "buttons": [],
        "children": [{
            "name": "PopOut2",
            "type": "UnityEngine.RectTransform",
            "x": 719.0799560546875,
            "y": 135.52000427246095,
            "instanceID": 28492,
            "buttons": ["PopOut2 (UnityEngine.UI.Button)"],
            "children": [{
                "name": "Text",
                "type": "UnityEngine.RectTransform",
                "x": 617.89599609375,
                "y": 135.52000427246095,
                "instanceID": 28324,
                "buttons": [],
                "children": []
            }]
        }]
    }, {
        "name": "PopOutMaster (2)",
        "type": "UnityEngine.RectTransform",
        "x": 835.2000122070313,
        "y": 72.27999877929688,
        "instanceID": 28716,
        "buttons": [],
        "children": [{
            "name": "PopOut3",
            "type": "UnityEngine.RectTransform",
            "x": 719.0799560546875,
            "y": 72.27999877929688,
            "instanceID": 28800,
            "buttons": ["PopOut3 (UnityEngine.UI.Button)"],
            "children": [{
                "name": "Text",
                "type": "UnityEngine.RectTransform",
                "x": 617.89599609375,
                "y": 72.27999877929688,
                "instanceID": 28442,
                "buttons": [],
                "children": []
            }]
        }]
    }, {
        "name": "BottomFade",
        "type": "UnityEngine.RectTransform",
        "x": 314.79595947265627,
        "y": 12.919998168945313,
        "instanceID": 28592,
        "buttons": [],
        "children": []
    }, {
        "name": "B4",
        "type": "UnityEngine.RectTransform",
        "x": 27.20001220703125,
        "y": 12.919998168945313,
        "instanceID": 28408,
        "buttons": ["B4 (UnityEngine.UI.Button)"],
        "children": [{
            "name": "Text",
            "type": "UnityEngine.RectTransform",
            "x": 27.20001220703125,
            "y": 12.919998168945313,
            "instanceID": 28690,
            "buttons": [],
            "children": []
        }]
    }, {
        "name": "ButtonSmall (1)",
        "type": "UnityEngine.RectTransform",
        "x": 81.60000610351563,
        "y": 12.919998168945313,
        "instanceID": 28698,
        "buttons": ["ButtonSmall (1) (UnityEngine.UI.Button)"],
        "children": [{
            "name": "Text",
            "type": "UnityEngine.RectTransform",
            "x": 81.60000610351563,
            "y": 12.919998168945313,
            "instanceID": 28484,
            "buttons": [],
            "children": []
        }]
    }, {
        "name": "ButtonSmall (2)",
        "type": "UnityEngine.RectTransform",
        "x": 136.0,
        "y": 12.919998168945313,
        "instanceID": 28380,
        "buttons": ["ButtonSmall (2) (UnityEngine.UI.Button)"],
        "children": [{
            "name": "Text",
            "type": "UnityEngine.RectTransform",
            "x": 136.0,
            "y": 12.919998168945313,
            "instanceID": 28734,
            "buttons": [],
            "children": []
        }]
    }, {
        "name": "ButtonSmall (3)",
        "type": "UnityEngine.RectTransform",
        "x": 190.39999389648438,
        "y": 12.919998168945313,
        "instanceID": 28650,
        "buttons": ["ButtonSmall (3) (UnityEngine.UI.Button)"],
        "children": [{
            "name": "Text",
            "type": "UnityEngine.RectTransform",
            "x": 190.39999389648438,
            "y": 12.919998168945313,
            "instanceID": 28568,
            "buttons": [],
            "children": []
        }]
    }, {
        "name": "ButtonSmall (4)",
        "type": "UnityEngine.RectTransform",
        "x": 244.8000030517578,
        "y": 12.919998168945313,
        "instanceID": 28556,
        "buttons": ["ButtonSmall (4) (UnityEngine.UI.Button)"],
        "children": [{
            "name": "Text",
            "type": "UnityEngine.RectTransform",
            "x": 244.8000030517578,
            "y": 12.919998168945313,
            "instanceID": 28842,
            "buttons": [],
            "children": []
        }]
    }, {
        "name": "ButtonSmall (5)",
        "type": "UnityEngine.RectTransform",
        "x": 299.20001220703127,
        "y": 12.919998168945313,
        "instanceID": 28678,
        "buttons": ["ButtonSmall (5) (UnityEngine.UI.Button)"],
        "children": [{
            "name": "Text",
            "type": "UnityEngine.RectTransform",
            "x": 299.20001220703127,
            "y": 12.919998168945313,
            "instanceID": 28814,
            "buttons": [],
            "children": []
        }]
    }, {
        "name": "ButtonSmall (6)",
        "type": "UnityEngine.RectTransform",
        "x": 353.6000061035156,
        "y": 12.919998168945313,
        "instanceID": 28822,
        "buttons": ["ButtonSmall (6) (UnityEngine.UI.Button)"],
        "children": [{
            "name": "Text",
            "type": "UnityEngine.RectTransform",
            "x": 353.6000061035156,
            "y": 12.919998168945313,
            "instanceID": 28670,
            "buttons": [],
            "children": []
        }]
    }, {
        "name": "Button (5)",
        "type": "UnityEngine.RectTransform",
        "x": 235.2109375,
        "y": 327.4600830078125,
        "instanceID": 28764,
        "buttons": ["Button (5) (UnityEngine.UI.Button)"],
        "children": [{
            "name": "Text",
            "type": "UnityEngine.RectTransform",
            "x": 235.2109375,
            "y": 327.4600830078125,
            "instanceID": 28400,
            "buttons": [],
            "children": []
        }]
    }, {
        "name": "Button (6)",
        "type": "UnityEngine.RectTransform",
        "x": 280.5690612792969,
        "y": 327.4600830078125,
        "instanceID": 28752,
        "buttons": ["Button (6) (UnityEngine.UI.Button)"],
        "children": [{
            "name": "Text",
            "type": "UnityEngine.RectTransform",
            "x": 280.5690612792969,
            "y": 327.4600830078125,
            "instanceID": 28468,
            "buttons": [],
            "children": []
        }]
    }, {
        "name": "Button (7)",
        "type": "UnityEngine.RectTransform",
        "x": 325.9245300292969,
        "y": 327.4600830078125,
        "instanceID": 28430,
        "buttons": ["Button (7) (UnityEngine.UI.Button)"],
        "children": [{
            "name": "Text",
            "type": "UnityEngine.RectTransform",
            "x": 325.9245300292969,
            "y": 327.4600830078125,
            "instanceID": 28392,
            "buttons": [],
            "children": []
        }]
    }, {
        "name": "Button (8)",
        "type": "UnityEngine.RectTransform",
        "x": 371.2799987792969,
        "y": 327.4600830078125,
        "instanceID": 28360,
        "buttons": ["Button (8) (UnityEngine.UI.Button)"],
        "children": [{
            "name": "Text",
            "type": "UnityEngine.RectTransform",
            "x": 371.2799987792969,
            "y": 327.4600830078125,
            "instanceID": 28532,
            "buttons": [],
            "children": []
        }]
    }, {
        "name": "START",
        "type": "UnityEngine.RectTransform",
        "x": 309.55999755859377,
        "y": 177.0,
        "instanceID": 28350,
        "buttons": ["START (UnityEngine.UI.Button)"],
        "children": [{
            "name": "Text",
            "type": "UnityEngine.RectTransform",
            "x": 309.55999755859377,
            "y": 177.0,
            "instanceID": 28584,
            "buttons": [],
            "children": []
        }]
    }],
    "buttons": ["TopFade (UnityEngine.UI.Button)", "Button (1) (UnityEngine.UI.Button)", "Button (2) (UnityEngine.UI.Button)", "Button (3) (UnityEngine.UI.Button)", "Button (4) (UnityEngine.UI.Button)", "PopOut1 (UnityEngine.UI.Button)", "PopOut2 (UnityEngine.UI.Button)", "PopOut3 (UnityEngine.UI.Button)", "B4 (UnityEngine.UI.Button)", "ButtonSmall (1) (UnityEngine.UI.Button)", "ButtonSmall (2) (UnityEngine.UI.Button)", "ButtonSmall (3) (UnityEngine.UI.Button)", "ButtonSmall (4) (UnityEngine.UI.Button)", "ButtonSmall (5) (UnityEngine.UI.Button)", "ButtonSmall (6) (UnityEngine.UI.Button)", "Button (5) (UnityEngine.UI.Button)", "Button (6) (UnityEngine.UI.Button)", "Button (7) (UnityEngine.UI.Button)", "Button (8) (UnityEngine.UI.Button)", "START (UnityEngine.UI.Button)"]
}

The JSON shown is a single object. There *is* no "table" to `foreach` over. Can you clarify why you expect to be able to do that? Would putting the single `Value` instance *into* an array/list after the deserialize step help? Why do you "need" to `foreach` over a single object? — Marc Gravell, Mar 22 '20 at 13:25
can you show the ``json`` returned by ``req.downloadHandler.text`` — Mohammed Sajid, Mar 22 '20 at 13:39
Well, I actually have a lot of items in the Json file. So I need to go through all of them and pick the correct one. That's why I need the foreach. I've posted the json file as an answer. So basically, I have something like 20 items like this one. And I want to pick this specific item among all others. — NicolasM, Mar 22 '20 at 14:01
Could you show your `Value` type? Also please include the received JSON content in your question. — derHugo, Mar 22 '20 at 14:47

derHugo · Accepted Answer · 2020-03-23T06:13:30.513

Now that you have posted the rest of the JSON I can see that you are trying to access an inner array wrapped within a bigger JSON object.

The code itself "worked" with a single Value because what you have there is a single JSON object, no array!

However, it wouldn't have any fields matching the entries in the JSON string so they would have their default values anyway.

So what you rather should have is actually that wrapper class that includes the relevant fields of your JSON

[Serializable]
public class JsonRoot
{
    public string scene;
    public Value[] gameObjectDefinitions;
}

then Deserialize into this type

var jsonRoot = JsonConverter.Deserialize<JsonRoot>(req.downloadHandler.text);

and now you can access and iterate over

foreach(var value in jsonRoot.gameObjectDefinitions)
{
    ...
}

An alternative here might be using SimpleJson

var jsonRoot = JSON.Parse(req.downloadHandler.text);
var values = jsonRoot["gameObjectDefinitions"].AsArray;

To your comment regarding the children:

You will find in the Value class they are simply non-existent so currently there is no way to access them.

If you want to represent the complete JSON format your classes should look like

[Serializable]
public class JsonRoot
{
    public string scene;
    public Value[] gameObjectDefinitions;
    public string[] buttons;
}

[Serializable]
public class Value
{
    public string name;
    public string type;
    public float x;
    public float y;
    public int instanceID;

    public string[] buttons;
    public Value[] children;
}

Note: Unity limits the serialiazation of such recursive type structures to a maximal nest level of 7! I don't know how the JSON library you are using handles this but be aware that there might exist this limitation.

I don't know what your final goal is but I guess the only way to iterate all children and subchildren would indeed be a recursive method like e.g.

...

foreach(var value in jsonRoot.gameObjectDefinitions)
{
    HandleValue(value);
}

...

private void HandleValue(Value value)
{
    ...

    if(value.children != null)
    {
        foreach(var child in value.children)
        {
            HandleValue(child);
        }
    }
}

Damn, I'm sorry to annoy you with that but I'm stuck here. Your solution works fine but I'm still facing an issue as I'm trying to reach PopOut1, PopOut2 and PopOut3. Those items are the children of PopOutMaster, PopOutMaster (1) and PopOutMaster (2). So when I'm going through my foreach loop, I can find PopOutMaster alright, but I can't figure out a way to access its children. Any idea how to do that ? — NicolasM, Mar 22 '20 at 23:51

Cannot deserialize the current JSON object (e.g. {"name":"value"}) into type 'Value[]' because the type requires a JSON array (e.g. [1,2,3])

1 Answers1