JSON.NET: Deserializing from JSON with LINQ

Question

I have following json:

{[
  "{\"Id\":3,\"ParentName\":\"TicketController\",\"ChildName\":null,\"Body\":\"Ticket\",\"ParentId\":null,\"HasChildren\":true,\"imageUrl\":null}",
  "{\"Id\":0,\"ParentName\":\"TicketController\",\"ChildName\":\"MainPage\",\"Body\":\"HomePage\",\"ParentId\":3,\"HasChildren\":false,\"imageUrl\":null}",
  "{\"Id\":1,\"ParentName\":\"TicketController\",\"ChildName\":\"TicketList\",\"Body\":\"Requests\",\"ParentId\":3,\"HasChildren\":false,\"imageUrl\":null}",
  "{\"Id\":2,\"ParentName\":\"TicketController\",\"ChildName\":\"Responses\",\"Body\":\"Responses\",\"ParentId\":3,\"HasChildren\":false,\"imageUrl\":null}",
  "{\"Id\":3,\"ParentName\":\"TicketController\",\"ChildName\":\"UpdateResponse\",\"Body\":\"Edit\",\"ParentId\":3,\"HasChildren\":false,\"imageUrl\":null}",
  "{\"Id\":4,\"ParentName\":\"TicketController\",\"ChildName\":\"UpdateResponse\",\"Body\":\"Update\",\"ParentId\":3,\"HasChildren\":false,\"imageUrl\":null}",
  "{\"Id\":5,\"ParentName\":\"TicketController\",\"ChildName\":\"RequestDetail\",\"Body\":\"Detail\",\"ParentId\":3,\"HasChildren\":false,\"imageUrl\":null}",
  "{\"Id\":6,\"ParentName\":\"TicketController\",\"ChildName\":\"RequestDetail\",\"Body\":\"Save\",\"ParentId\":3,\"HasChildren\":false,\"imageUrl\":null}",
  "{\"Id\":7,\"ParentName\":\"TicketController\",\"ChildName\":\"DeleteRequest\",\"Body\":\"Delete\",\"ParentId\":3,\"HasChildren\":false,\"imageUrl\":null}"
]}

The result is generated by selecting some checkboxes (KendoUI tree view witch checkbox) in client side by users:

var checkedNodes = [];
function checkedNodeIds(nodes) {
    for (var i = 0; i < nodes.length; i++) {
        if (nodes[i].checked) {
            var page = {
                Id: nodes[i].Id,
                ParentName: nodes[i].ParentName,
                ChildName: nodes[i].ChildName,
                Body: nodes[i].Body,
                ParentId: nodes[i].ParentId,
                HasChildren: nodes[i].HasChildren,
                imageUrl: nodes[i].imageUrl
            };
            checkedNodes.push(JSON.stringify(page));
            console.log(nodes[i]);
        }

        if (nodes[i].hasChildren) {
            checkedNodeIds(nodes[i].children.view(), checkedNodes);
        }
    }
}
$('#btnSave').click(function() {
    var tv = $("#my-treeview").data("kendoTreeView");
    checkedNodeIds(tv.dataSource.view());
    var data = {};
    data.checks = JSON.stringify(checkedNodes);
    $.ajax({
        url: '@Url.Action("SaveTreeViewData", "Main", new {area = ""})',
        type: 'POST',
        data: data,
        dataType: 'json',
        success: function(result) {
            alert("Success");
        },
        error: function(result) {
            alert("Error");
        }
    });
});

In server side I'm using this action method for parsing the json result:

[HttpPost]
public ActionResult SaveTreeViewData(string checks) {
    //var result = JsonConvert.DeserializeObject<Page[]>(checks.Substring(1, checks.Length-2));
    var jsonArray = JArray.Parse(checks);
    IList < Page > pages = jsonArray.Select(p = > new Page {
        Id = (int) p["Id"],
        ParentName = (string) p["ParentName"],
        ChildName = (string) p["ChildName"] ? ? "NoChild",
        ParentId = (int) p["ParentId"],
        HasChildren = (bool) p["HasChildren"],
        Body = (string) p["Body"],
        imageUrl = (string) p["imageUrl"]
    }).ToList();

    return Json("ok");
}

But when I click on save button I'm getting this exception:

{"Cannot access child value on Newtonsoft.Json.Linq.JValue."}

Any idea?

ParentId = (int) p["ParentId"] Seems fishy... I see at least one element with ParentId null. — xanatos
– xanatos, Commented May 26, 2015 at 12:01

Jon Skeet · Accepted Answer · 2015-05-26 12:00:39Z

3

Each element in your array is just another string - so you need to parse each of those as well. For example:

IList<Page> pages = jsonArray
    .Select(text => JObject.Parse(text))
    .Select(p => new Page { ... })
    .ToList();

Alternatively, change your Javascript code to avoid the double-encoding, so you end up with JSON of:

{[
  {"Id":3,"ParentName":"TicketController",""ChildName"":null,"Body":"Ticket","ParentId":null,"HasChildren":true,"imageUrl":null},
  ...

]}

answered May 26, 2015 at 12:00

Jon Skeet

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1 Comment

Sirwan Afifi Over a year ago

Wow! Thank you so much Jon :) PS: text needs .ToString() :)

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