Djama Djama - 6 months ago 723
JSON Question

Cannot deserialize the current JSON array (e.g. [1,2,3])

I am trying to read my JSON result.

Here is my RootObject

public class RootObject
{
public int id { get; set; }
public bool is_default { get; set; }
public string name { get; set; }
public int quantity { get; set; }
public string stock { get; set; }
public string unit_cost { get; set; }
}


Here is my JSON result

[{"id": 3636, "is_default": true, "name": "Unit", "quantity": 1, "stock": "100000.00", "unit_cost": "0"}, {"id": 4592, "is_default": false, "name": "Bundle", "quantity": 5, "stock": "100000.00", "unit_cost": "0"}]


Here is my code to read the result

public static RootObject GetItems(string user, string key, Int32 tid, Int32 pid)
{
// Customize URL according to geo location parameters
var url = string.Format(uniqueItemUrl, user, key, tid, pid);

// Syncronious Consumption
var syncClient = new WebClient();

var content = syncClient.DownloadString(url);

return JsonConvert.DeserializeObject<RootObject>(content);

}


But I am having a problem with this error :


Cannot deserialize the current JSON array (e.g. [1,2,3]) into type 'avaris_cash_salepoint.BL.UniqueItemDataRootObject' because the type
requires a JSON object (e.g. {"name":"value"}) to deserialize
correctly. To fix this error either change the JSON to a JSON object
(e.g. {"name":"value"}) or change the deserialized type to an array or
a type that implements a collection interface (e.g. ICollection,
IList) like List that can be deserialized from a JSON array.
JsonArrayAttribute can also be added to the type to force it to
deserialize from a JSON array. Path '', line 1, position 1.


at this line:
return JsonConvert.DeserializeObject(content);

Any help to fix this error ?

Answer

I think the problem you're having is that your JSON is a list of objects when it comes in and it doesnt directly relate to your root class.

var content would look something like this (i assume):

[
  {
    "id": 3636,
    "is_default": true,
    "name": "Unit",
    "quantity": 1,
    "stock": "100000.00",
    "unit_cost": "0"
  },
  {
    "id": 4592,
    "is_default": false,
    "name": "Bundle",
    "quantity": 5,
    "stock": "100000.00",
    "unit_cost": "0"
  }
]

Note: make use of http://jsonviewer.stack.hu/ to format your JSON.

So if you try the following it should work:

  public static List<RootObject> GetItems(string user, string key, Int32 tid, Int32 pid)
    {
        // Customize URL according to geo location parameters
        var url = string.Format(uniqueItemUrl, user, key, tid, pid);

        // Syncronious Consumption
        var syncClient = new WebClient();

        var content = syncClient.DownloadString(url);

        return JsonConvert.DeserializeObject<List<RootObject>>(content);

    }

You will need to then iterate if you don't wish to return a list of RootObject.


I went ahead and tested this in a Console app, worked fine.

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