Json.NET not deserialzing nested object

Question

I'm trying to use Json.NET to serialize and deserialze a tree structure for jsTree.

Here are the class definitions:

private class Metadata
    {
        [JsonProperty(PropertyName = "nodeType")]
        public NodeType NodeType;

        [JsonProperty(PropertyName = "typeDepth")]
        public int TypeDepth;
    }

    private class TreeNode
    {
        [JsonProperty(PropertyName = "data")]
        public String Title;

        [JsonIgnore]
        public NodeType NodeType;

        [JsonIgnore] 
        public int TypeDepth;

        [JsonProperty(PropertyName = "children", NullValueHandling = NullValueHandling.Ignore)]
        public List<TreeNode> Children;

        [JsonProperty(PropertyName = "metadata")]
        public Metadata Metadata
        {
            get
            {
                return new Metadata() {NodeType = NodeType, TypeDepth = TypeDepth};
            }

            set { 
                TypeDepth = value.TypeDepth;
                NodeType = value.NodeType;
            }
        }

        private ItemGroup _itemGroup;

        [JsonIgnore]
        public ItemGroup ItemGroup
        {
            get
            {
                if(this.NodeType != NodeType.ItemGroup)
                    throw new InvalidDataException();

                return _itemGroup;
            }

            set { _itemGroup = value; }
        }
    }

And here is some example JSON:

[{
"data":"Strands",
"attr":{"class":""},
"state":"open",
"metadata":{
    "nodeType":3,
    "typeDepth":0},
"children":[{
    "data":"Math",
    "attr":{"class":"","rel":"itemGroup"},
    "state":"open",
    "metadata":{
        "nodeType":1,
        "typeDepth":0},
    "children":[{
        "data":"Subjects",
        "attr":{"class":""},
        "state":"open",
        "metadata":{"nodeType":3,"typeDepth":1},
        "children":[{
            "data":"Algebra 1",
            "attr":{"class":"","rel":"itemGroup"},
            "state":"open",
            "metadata":{
                "nodeType":1,
                "typeDepth":1},
            "children":[{
                "data":"Clusters",
                "attr":{"class":""},
                "state":"open",
                "metadata":{
                    "nodeType":3,
                    "typeDepth":2},
                "children":[{
                    "data":"Factoring",
                    "attr":{"rel":"itemGroup"},
                    "metadata":{
                        "nodeType":1,
                        "typeDepth":2}},
                    {"data":"Substitution",
                    "attr":{"class":"","rel":"itemGroup"},
                    "metadata":{"nodeType":1,"typeDepth":2}}]}]}]}]}]}]

I try to deserialize like this: List<TreeNode> tree = (List<TreeNode>)JsonConvert.DeserializeObject(form["treeJson"], typeof (List<TreeNode>));

The tree structure is deserialized correctly, but none of the nodes have Metadata.

Anyone see what's going wrong here?

Thanks!

L.B · Accepted Answer · 2012-06-18 20:29:49Z

1

When i change Metadata property as

[JsonProperty(PropertyName = "metadata")]
public Metadata Metadata { get; set; }

it seems to work fine

var tree = JsonConvert.DeserializeObject<List<TreeNode>>(jsonstring);

Any reason for implementing it as

[JsonProperty(PropertyName = "metadata")]
public Metadata Metadata
{
    get
    {
        return new Metadata() {NodeType = NodeType, TypeDepth = TypeDepth};
    }
    set { 
          TypeDepth = value.TypeDepth;
           NodeType = value.NodeType;
    }
}

?

edited Jun 18, 2012 at 20:29

answered Jun 18, 2012 at 20:24

L.B

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1 Comment

nw. Over a year ago

The property was implemented as such to make the existing tree code compatible with jsTree. Was wondering if that setter had something to do with it, but didn't want to change a bunch of code on a hunch. Thanks.

Steve Konves · Accepted Answer · 2012-06-18 18:55:59Z

0

The class metadata is private. From what I know, this will prevent the Json serializer from accessing it; therefore, it will leave the property value null;

answered Jun 18, 2012 at 18:55

Steve Konves

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1 Comment

nw. Over a year ago

Hmm, still not working after changing class to public. Any other ideas?

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