CODEWITHSUNDEEP
c#jsonjson.net
trailerman
trailerman

Reputation: 321

JSON error message while Deserializing using the JSON Text Reader

I am getting this error when trying to read JSON from a stream:

Newtonsoft.Json.JsonSerializationException: 'Unexpected JSON token when reading DataTable. Expected StartArray, got String. Path 'Data.GUID', line 1, position 110.'

Error is on the line syncResult = serializer.Deserialize<cls_Sync.SyncResult>(json)

cls_Sync.SyncResult syncResult = new cls_Sync.SyncResult();
using (var stream = await response.Content.ReadAsStreamAsync())
{
    using (var reader = new StreamReader(stream))
    {
        //reader.ReadToEnd();
        using (var json = new JsonTextReader(reader))
        {
            syncResult = serializer.Deserialize<cls_Sync.SyncResult>(json);
        }
    }
}

This is the structure of the class:

public class SyncResult
{
    public Guid GUID;
    public bool IsSuccessful;
    public string Message;
    public string SQL;
    public DataSet Data;
    public List<Guid> SyncResultGUIDs;
    public Guid LastSyncGUID;

    public SyncResult();
}

Sample JSON:

{
   "ContentEncoding": null,
   "ContentType": "Application/json",
   "Data": {
      "GUID": "00000000-0000-0000-0000-000000000000",
      "IsSuccessful": true,
      "Message": null,
      "SQL": null,
      "Data": {
         "Table": []
      },
      "SyncResultGUIDs": [],
      "LastSyncGUID": "00000000-0000-0000-0000-000000000000"
   },
   "JsonRequestBehavior": 0,
   "MaxJsonLength": null,
   "RecursionLimit": null
}

Upvotes: 0

Views: 206

Answers (1)

Brian Rogers
Brian Rogers

Reputation: 129707

The problem is you are missing an outer class. You are attempting to deserialize into a SyncResult, but that object is actually one level further down in the JSON.

Try defining the following wrapper class:

public class ResultWrapper
{
    public string ContentEncoding { get; set; }
    public string ContentType { get; set; }
    public SyncResult Data { get; set; }
    public long JsonRequestBehavior { get; set; }
    public int? MaxJsonLength { get; set; }
    public int? RecursionLimit { get; set; }
}

Then deserialize into the wrapper and get the SyncResult from that:

syncResult = serializer.Deserialize<ResultWrapper>(json).Data;

Fiddle: https://dotnetfiddle.net/0uY9Yo

Note: you can omit any properties from the wrapper that you do not actually need. If all you need is the SyncResult then the wrapper could be as simple as this:

public class ResultWrapper
{
    public SyncResult Data { get; set; }
}

Upvotes: 2

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