JSON file to Datatable error

Question

2.00/5 (1 vote)

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Hi Experts,
I managed to get json file using HttpWebRequest.
And I used JSON.net to convert json file to Datatable.
when trying to convert it give me the following error:

C#

Unexpected JSON token when reading DataTable. Expected StartArray, got StartObject. Path '', line 1, position 1.

Here's my c# code:

C#

HttpWebRequest httpWebRequest = (HttpWebRequest)WebRequest.Create("http://abc.com/makes.json");
            httpWebRequest.Method = WebRequestMethods.Http.Get;
            httpWebRequest.Accept = "application/json; charset=utf-8";
            string file;
            var response=(HttpWebResponse)httpWebRequest.GetResponse();
            using (var sr = new StreamReader(response.GetResponseStream()))
            {
                file = sr.ReadToEnd();
            }

            //var json = JObject.Parse(file);
            var table = JsonConvert.DeserializeObject<DataTable>(file);
            if (table.Rows.Count > 0)
            { 
                //do something 
            }

here is how the file looks like:

C#

{"makes":[{"makeid":21,"name":"Acura"},{"makeid":250,"name":"AM GENERAL"},{"makeid":5,"name":"Audi"},{"makeid":239,"name":"BMW"},{"makeid":65,"name":"Buick"},{"makeid":66,"name":"Cadillac"},{"makeid":1,"name":"Chevrolet"},{"makeid":10,"name":"Chrysler"},{"makeid":9,"name":"Dodge"},{"makeid":2,"name":"Ford"},{"makeid":11,"name":"GMC"},{"makeid":13,"name":"Honda"},{"makeid":117,"name":"Hummer"},{"makeid":19,"name":"Hyundai"},{"makeid":123,"name":"Infiniti"},{"makeid":240,"name":"Isuzu"},{"makeid":242,"name":"Jaguar"},{"makeid":130,"name":"Jeep"},{"makeid":18,"name":"Kia"},{"makeid":321,"name":"Lada"},{"makeid":244,"name":"Land Rover"},{"makeid":143,"name":"Lexus"},{"makeid":144,"name":"Lincoln"},{"makeid":15,"name":"Mazda"},{"makeid":245,"name":"Mercedes-Benz"},{"makeid":152,"name":"Mercury"},{"makeid":241,"name":"Mini"},{"makeid":158,"name":"Mitsubishi"},{"makeid":14,"name":"Nissan"},{"makeid":167,"name":"Oldsmobile"},{"makeid":281,"name":"Opel"},{"makeid":180,"name":"Plymouth"},{"makeid":181,"name":"Pontiac"},{"makeid":17,"name":"Porsche"},{"makeid":311,"name":"RAM"},{"makeid":331,"name":"Renault"},{"makeid":238,"name":"Saab"},{"makeid":12,"name":"Saturn"},{"makeid":243,"name":"Scion"},{"makeid":202,"name":"Subaru"},{"makeid":204,"name":"Suzuki"},{"makeid":209,"name":"Toyota"},{"makeid":16,"name":"Volkswagen"},{"makeid":6,"name":"Volvo"},{"makeid":301,"name":"VPG"}]}

But when giving this format (manually) it works!

C#

file= "[    {      \"makeid\": 21,      \"name\": \"Acura\"    },    {      \"makeid\": 250,      \"name\": \"AM GENERAL\"    },    {      \"makeid\": 5,      \"name\": \"Audi\"    },    {      \"makeid\": 239,      \"name\": \"BMW\"    },    {      \"makeid\": 65,      \"name\": \"Buick\"    },    {      \"makeid\": 66,      \"name\": \"Cadillac\"    },    {      \"makeid\": 1,      \"name\": \"Chevrolet\"    },    {      \"makeid\": 10,      \"name\": \"Chrysler\"    },    {      \"makeid\": 9,      \"name\": \"Dodge\"    },    {      \"makeid\": 2,      \"name\": \"Ford\"    },    {      \"makeid\": 11,      \"name\": \"GMC\"    },    {      \"makeid\": 13,      \"name\": \"Honda\"    },    {      \"makeid\": 117,      \"name\": \"Hummer\"    },    {      \"makeid\": 19,      \"name\": \"Hyundai\"    },    {      \"makeid\": 123,      \"name\": \"Infiniti\"    },    {      \"makeid\": 240,      \"name\": \"Isuzu\"    },    {      \"makeid\": 242,      \"name\": \"Jaguar\"    },    {      \"makeid\": 130,      \"name\": \"Jeep\"    },    {      \"makeid\": 18,      \"name\": \"Kia\"    },    {      \"makeid\": 321,      \"name\": \"Lada\"    },    {      \"makeid\": 244,      \"name\": \"Land Rover\"    },    {      \"makeid\": 143,      \"name\": \"Lexus\"    },    {      \"makeid\": 144,      \"name\": \"Lincoln\"    },    {      \"makeid\": 15,      \"name\": \"Mazda\"    },    {      \"makeid\": 245,      \"name\": \"Mercedes-Benz\"    },    {      \"makeid\": 152,      \"name\": \"Mercury\"    },    {      \"makeid\": 241,      \"name\": \"Mini\"    },    {      \"makeid\": 158,      \"name\": \"Mitsubishi\"    },    {      \"makeid\": 14,      \"name\": \"Nissan\"    },    {      \"makeid\": 167,      \"name\": \"Oldsmobile\"    },    {      \"makeid\": 281,      \"name\": \"Opel\"    },    {      \"makeid\": 180,      \"name\": \"Plymouth\"    },    {      \"makeid\": 181,      \"name\": \"Pontiac\"    },    {      \"makeid\": 17,      \"name\": \"Porsche\"    },    {      \"makeid\": 311,      \"name\": \"RAM\"    },    {      \"makeid\": 331,      \"name\": \"Renault\"    },    {      \"makeid\": 238,      \"name\": \"Saab\"    },    {      \"makeid\": 12,      \"name\": \"Saturn\"    },    {      \"makeid\": 243,      \"name\": \"Scion\"    },    {      \"makeid\": 202,      \"name\": \"Subaru\"    },    {      \"makeid\": 204,      \"name\": \"Suzuki\"    },    {      \"makeid\": 209,      \"name\": \"Toyota\"    },    {      \"makeid\": 16,      \"name\": \"Volkswagen\"    },    {      \"makeid\": 6,      \"name\": \"Volvo\"    },    {      \"makeid\": 301,      \"name\": \"VPG\"    }  ]";

please advise what's wrong with my code. I can't do it manually everytime. i need to read json files from url then convert them to datatables to be saved to DB.

thanks
Samira

Posted 2-Dec-15 9:45am

Samira Radwan

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Richard Deeming · Accepted Answer · 2015-12-02T10:23:00

Solution 1

Assuming the JSON you're receiving always looks the same, use the DeserializeAnonymousType method[^]:

C#

var table = JsonConvert.DeserializeAnonymousType(file, new { Makes = default(DataTable) }).Makes;

Posted 2-Dec-15 10:23am

Richard Deeming

Comments

Samira Radwan 2-Dec-15 16:30pm

thanks a lot saved me a lot of time :)

BillWoodruff 2-Dec-15 23:10pm

+5 Wow ! Never heard of the Newton method before; wonder if MS JSON, or Mehdi Gholam's JSON would have either a similar problem, or a similar method (that's not to imply I understand what the OP's problem is!).