Get json array from Web api into c#

Question

I´m having a SQL database and I want to get the SQL values from a API into c# code. The API contains multiple rooms with room attributes, and each room have a Guid as a id.

This code works but I only get one room out of this:

string url = "https://api.booking.com/api/room/35bf3c4d-9b5b-40fd-bcf4-a4c2c6c564bc";

HttpClient client = new HttpClient();

string response = await client.GetStringAsync(url);

var data = JsonConvert.DeserializeObject<Class2>(response);

When i remove the id (Guid) to get all rooms i get this error when i launch the application:

Newtonsoft.Json.JsonSerializationException: 'Cannot deserialize the current JSON array (e.g. [1,2,3]) into type 'Class2' 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.'

This is the code without the Guid:

string url = "https://api.booking.com/api/room";

HttpClient client = new HttpClient();

string response = await client.GetStringAsync(url);

var data = JsonConvert.DeserializeObject<Class2>(response);

My question is in short terms "How can i get a json array from a api?".

Thanks in advance!

Edit:

This is the code for class2:

public class Class2
{
    public string name { get; set; }
    public string id { get; set; }
    public int seats { get; set; }
    public int? availableFrom { get; set; }
    public int? availableTo { get; set; }
}

And this is a longer output from a room in the API:

[
{
    "name": "Rum 1",
    "id": "a31d1fc8-df29-419c-8308-f8bc884b378e",
    "seats": 10,
    "availableFrom": null,
    "availableTo": null
  },
  {
    "name": "Rum 2",
    "id": "7defd34d-222d-4980-b28f-e616e8b9003c",
    "seats": 5,
    "availableFrom": null,
    "availableTo": null
  },
  {
    "name": "Skrubben",
    "id": "b20390ff-703b-4d80-8c2f-32c0f27158bc",
    "seats": 5,
    "availableFrom": 10,
    "availableTo": 11
  },
  {
    "name": "Hangaren",
    "id": "b89cbacd-c738-477f-aff2-7f22c2b2cd5c",
    "seats": 100,
    "availableFrom": null,
    "availableTo": null
  },
  {
    "name": "Tv-rummet",
    "id": "ea6a290f-209b-4ccb-91a4-65d82a674bad",
    "seats": 10,
    "availableFrom": null,
    "availableTo": null
  },
  {
    "name": "Projektor-rummet",
    "id": "3136a56a-4a28-4939-aca8-806534c808f7",
    "seats": 12,
    "availableFrom": null,
    "availableTo": null
  },
  {
    "name": "Skolsalen",
    "id": "05f73582-3734-453f-aeb3-36daf8884912",
    "seats": 30,
    "availableFrom": null,
    "availableTo": null
  }
]

When I do that i cant reach all the attributes inside the rooms (for example Name) @DmitryEgorov — luddep
– luddep, Commented May 25, 2018 at 9:41
Perhaps, objects returned in the array by .../api/room are not as detailed as a single object instance returned by .../api/room/{guid}. Could you please provide a sample output of the two API requests and Class2 definition as well? — Dmitry Egorov
– Dmitry Egorov, Commented May 25, 2018 at 9:45
Seems to be output from .../api/room/{guid}. What's the output from .../api/room? — Dmitry Egorov
– Dmitry Egorov, Commented May 25, 2018 at 10:00

Sahil Sharma · Accepted Answer · 2018-05-25 10:16:14Z

5

As the error suggests,

You are deserializing an array into a class. It will never work. You need to deserialize it into either an array or a list using the below code snippet.

Try:
var data = JsonConvert.DeserializeObject<List<Class2>>(response);
or
var data = JsonConvert.DeserializeObject<Class2[]>(response);
and it will work fine.

EDIT 1:

foreach(var room in data)
{
   string id = room.id;
   string name = room.name;

   // and so on
}

edited May 25, 2018 at 10:16

answered May 25, 2018 at 9:43

Sahil Sharma

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6 Comments

luddep Over a year ago

Okey, i tried the first example but when i do that i can't reach the attributes in the rooms.

Sahil Sharma Over a year ago

With first example, you get a list of rooms. Now try to iterate it using a foreach loop and find the attributes.

luddep Over a year ago

Okey, i will come back with the results :)

Sahil Sharma Over a year ago

Sure, post the code snippet if possible for more clarity.

luddep Over a year ago

Haha, sorry but i don't really have the knowledge to write the foreach loop :(

|

MerlinMa · Accepted Answer · 2018-05-25 09:45:17Z

0

multiple Class2 objects must be use List or Array type to convert them， you can try JsonConvert.DeserializeObject<List<Class2>>(response)

answered May 25, 2018 at 9:45

MerlinMa

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