We Keep Coding

Deserializing JSON with Newtonsoft, using a specific class

I know there are lots of questions on how to do this...
I have a pretty complex JSON returned from an API and I am trying to work my way through it. I simplified the JSON answer so it holds one of the immanent problems.
The simplified JSON answer
{"data":[{"type":"task","id":"10118"},{"type":"task","id":"10004"}]}
My class to be used for the deserialisation
namespace TestJsonDeserializeApp
{
class jsonTask
{
public List<Data> data { get; set; }
public class Data
{
public string id { get; set; }
public string type { get; set; }
}
}
}
How I want to do the deserialisation
List<jsonTask> test = JsonConvert.DeserializeObject<List<jsonTask>>(strJSON);
and finally the error message I am getting
Cannot deserialize the current JSON object (e.g. {"name":"value"}) into type 'System.Collections.Generic.List`1[TestJsonDeserializeApp.jsonTask]' because the type requires a JSON array (e.g. [1,2,3]) to deserialize correctly.
To fix this error either change the JSON to a JSON array (e.g. [1,2,3]) or change the deserialized type so that it is a normal .NET type (e.g. not a primitive type like integer, not a collection type like an array or List) that can be deserialized from a JSON object. JsonObjectAttribute can also be added to the type to force it to deserialize from a JSON object.
Path 'data', line 1, position 8.
Can one of you tell me how I have to write the jsonTask class to fit the structure of the JSON input?

Copy your JSON. Open Visual studio. Create new C# class file. Now Select below menu option:
Edit > Paste Special > Paste JSON as classes
This will create a class as below
public class Rootobject
{
public Datum[] data { get; set; }
}
public class Datum
{
public string type { get; set; }
public string id { get; set; }
}
Now change RootObject to jsonTask and deserialise as below
jsonTask test = JsonConvert.DeserializeObject<jsonTask>(strJSON);

With your code you are casting the strJSON to List with a list. You need to remove the outer list since jsonTask alreadyhas the public List data { get; set; }
Try:
jsonTask test = JsonConvert.DeserializeObject(strJSON);

How to Deserialize JSON data? C#

Im getting a Json Data from an API and i have been trying to deserialize.
Json data:
{
   "items": [
      {
         "id": "1",
         "name": "samplename",
         "AddressList1": {
            "City": "Hyd",
            "State": "TN",
            "Country": "IN"
         },
         "Age": "10"
      },
      {
         "id": "2",
         "name": "samplename2",
         "AddressList1": {
            "City": "Hydd",
            "State": "TN",
            "Country": "IN"
         },
         "Age": "10"
      }
   ],
   "paging": {
      "cursors": {}
   }
}
Entities:
public class AddressList1
{
public string City { get; set; }
public string State { get; set; }
public string Country { get; set; }
}
public class Item
{
public string id { get; set; }
public string name { get; set; }
public AddressList1 addressList1 { get; set; }
public string Age { get; set; }
}
public class Cursors
{
}
public class Paging
{
public Cursors cursors { get; set; }
}
public class Users
{
public List<Item> items { get; set; }
public Paging paging { get; set; }
}
C# code:
JsonConvert.DeserializeObject<List<Users>>(content);
Error Message:
Cannot deserialize the current JSON object (e.g. {"name":"value"})
into type 'System.Collections.Generic.List`1[Entities.Users]'
because the type requires a JSON array (e.g. [1,2,3]) to deserialize
correctly.
where am i doing wrong?

The following is a JSON-object; in your case a User
{ ... }
The following is a JSON-array; in your case an array of User
[ { ... }, { ... } ]
Thus if you want to deserialize the JSON you got into an array of Users this is not possible because you have no array in JSON.
Therefore the right code to deserialize is:
JsonConvert.DeserializeObject<Users>(content);
Furthermore your mapping is erroneous because in JSON there is a property AddressList1 and in the class it is called addressList1

Given your JSON, you would need a POCO object that contains a items member and a paging member.
JsonConvert.DeserializeObject<Users>(content);
should work.

Your Json string is good formatted and the entities are according to Json2Csharp good too.
but your problem is with the instruction JsonConvert.DeserializeObject<List<Users>>(content);
all that json that you have is only ONE User, and you are trying to get a list of them, there is the issue,
you can try instead with:
JsonConvert.DeserializeObject<Users>(content);

Try Below Code
JsonConvert.DeserializeObject<Users>(content);

Your entities(models) look just fine. If you are using, or were to use ASP.NET Web API 2, and your client is using the http verb post for example, this setup would work as Web API takes care of the object deserialization:
public HttpStatusCode Post(Item item)
{
Debug.Write(item.toString());
return HttpStatusCode.OK;
}
If you insist in deserializing manually then use the JavaScriptSerializer library which allows you to do things like:
Item item = new JavaScriptSerializer().Deserialize<Item>(content);
Notice that .Deserialize<T>() takes a generic which in your case it Item.
Hope that helps.

Deserializing an array of objects with Json.Net

The received data is like this:
Inside each item, there is an object, customer, I have an identical class for that. How can I convert them using Json.net?
I have tried the followings:
var data = JsonConvert.DeserializeObject<List<customer>>(val);
and adding another class:
public class customerJson
{
public Customer customer{ get; set; }
}
And trying to deserialize it:
var data = JsonConvert.DeserializeObject<List<customerJson>>(val);
With both of them I get an exception:
Cannot deserialize the current JSON object (e.g. {"name":"value"}) into type 'System.Collections.Generic.List`1[customer]' because the type requires a JSON array (e.g. [1,2,3]) to deserialize correctly.
To fix this error either change the JSON to a JSON array (e.g. [1,2,3]) or change the deserialized type so that it is a normal .NET type (e.g. not a primitive type like integer, not a collection type like an array or List) that can be deserialized from a JSON object. JsonObjectAttribute can also be added to the type to force it to deserialize from a JSON object.
Path 'rows', line 1, position 8.
Data:
{"rows":[{"id":"232333","name":"nam"},{"id":"3434444","name":"2ndName"}]}

If I read your json data structure correctly you would want this:
public class Root
{
public List<Customer> rows { get; set; }
}
and
var data = JsonConvert.DeserializeObject<Root>(val);
Tested code:
void Main()
{
var test = JsonConvert.DeserializeObject<Root>("{\"rows\":[{\"id\":\"232333\",\"name\":\"nam\"},{\"id\":\"3434444\",\"name\":\"2ndName\"}]}");
Console.WriteLine(test.rows[0].id); // prints 232333
}
public class Customer
{
public int id { get; set; }
}
public class Root
{
public List<Customer> rows { get; set; }
}

Just in case anyone is still having issues. This worked out for me:
If the Json looks something like this:
"result": [
{
"firstname": "John",
"lastname": "Doe",
},
{
"firstname": "Max",
"lastname": "Mustermann",
}
]
ResultList.cs
public class ResultList {
[JsonProperty("result")]
public List<ResultObj> ResultObj { get; set }
}
ResultObj.cs
public class ResultObj {
[JsonProperty("firstname")]
public string FirstName { get; set; }
[JsonProperty("lastname")]
public string LastName{ get; set; }
}
And finally:
using Newtonsoft.Json;
var resultList = JsonConvert.DeserializeObject<ResultList>(jsonString);

Converting JSON to List

I am stuck in a step that I am sure should work. I have a method (in a separate class) that should return a List as its value after processing the JSON. I am going to paste the code skipping the JSON configuration stuff:
public static dynamic CustInformation(string Identifier)
{
//SKIPPED JSON CONFIG STUFF (IT'S WORKING CORRECTLY)
var result = "";
var httpResponse = (HttpWebResponse)httpWebRequest.GetResponse();
dynamic d;
using (var streamReader = new StreamReader(httpResponse.GetResponseStream()))
{
result = streamReader.ReadToEnd();
}
return JsonConvert.DeserializeObject<List<Models.RootObject>>(result);
}
The model was generated using C# to Json converter:
public class Record
{
public string idIdentifier { get; set; }
public string KnowName1 { get; set; }
public string KnowAddress1 { get; set; }
public string KnowRelation1 { get; set; }
public string KnowPhone1 { get; set; }
public string KnowName2 { get; set; }
public string KnowAddress2 { get; set; }
//.....skipped other variables
}
public class RootObject
{
public List<Record> record { get; set; }
}
And I am calling the method like this:
var model = Classes.EndPoint.CustInformation(identifier);
Yet I am getting this error everytime:
Cannot deserialize the current JSON object (e.g. {"name":"value"}) into type 'System.Collections.Generic.List`1[Models.RootObject]' because the type requires a JSON array (e.g. [1,2,3]) to deserialize correctly.
To fix this error either change the JSON to a JSON array (e.g. [1,2,3]) or change
the deserialized type so that it is a normal .NET type (e.g. not a primitive type like integer, not a collection type like an array or List<T>) that can be deserialized from a JSON object. JsonObjectAttribute can also be added to the type to force it to deserialize from a JSON object.
Path 'record', line 1, position 10.
EDIT: JSON
{
"record": [
{
Identifier": "DQRJO1Q0IQRS",
"KnowName1": "",
"KnowAddress1": "",
"KnowRelation1": "",
"KnowPhone1": "",
"KnowName2": "",
"KnowAddress2": "",
//.....MORE STYFF
}
]
}

Like I said in the comments, and like the error message clearly states, you're trying to deserialize into a list of root objects, but your JSON is only one root object, not an array.
Here's what your C# should be.
return JsonConvert.DeserializeObject<Models.RootObject>(result);

Questioning received JSON structure

I'm currently using a beta API (http://developer.riotgames.com/api/methods) which returns JSON for all the exposed methods.
I've been able to use JSON.NET to deserialize all of these return values so far. However, today I consumed one of their function which returns a JSON that is valid but is in my opinion not correct.
You're probably wondering, why don't you ask it on the beta forum? I have but I haven't received an answer so far and in general this intrigues me.
A snippet of the JSON return:
"1001": {
"name": "Boots of Speed",
"plaintext": "Slightly increases Movement Speed",
"group": "BootsNormal",
"description": "<...
}
The problem I have with this structure is that the ID is used as a "group" without an identifier. I would be able to use this decently if it had
"ItemID" : "1001"
But it doesn't have that. I don't mind manually parsing it but I'd first like to know whether or not this JSON is correct (not just valid).
Do you agree that this is not a clean way of creating a JSON block that contains a list of elements or am I missing something here? So far I haven't seen any comments on the beta forum of this API so I'm really wondering why.
Edit "valid" vs "correct/usable":
I know it's a valid JSON statement. I'm questioning the fact whether this is usable with JSON.NET.
I have the following class definition (with two subclasses):
public class JSONItem
{
[JsonProperty("tags")]
public string[] Tags { get; set; }
[JsonProperty("plaintext")]
public string Plaintext { get; set; }
[JsonProperty("description")]
public string Description { get; set; }
[JsonProperty("name")]
public string Name { get; set; }
[JsonProperty("into")]
public string[] Into { get; set; }
[JsonProperty("image")]
public JSONItemImage Image { get; set; }
[JsonProperty("colloq")]
public string Colloq { get; set; }
[JsonProperty("gold")]
public JSONItemGold Gold { get; set; }
}
When giving the above JSON block to to JSONConvert.DeserializeObject(json) it throws an error because "1001" is not mentioned in JSONItem.
How do you handle this so that you can use JSON.NET?
A class like this won't work because you have no names to give the properties:
public class JSONItemWrapper
{
[JsonProperty("")]
public string ID { get; set; }
[JsonProperty("")]
public JSONItem MyProperty { get; set; }
}
Edit: "consistent with other methods"
The other methods return blocks where every property is within {} and has an identifier. The most recently added function have this "primary key outside of {}" style.

It is a valid json and you can use a type like Dictionary<string, SomeObject> to deserialize your json.
string json = #"{
""1001"": {
""name"": ""Boots of Speed"",
""plaintext"": ""Slightly increases Movement Speed"",
""group"": ""BootsNormal"",
""description"": ""desc...""
}
}";
var dict = JsonConvert.DeserializeObject<Dictionary<string, MyObject>>(json);
and accesing an item later on by its key can be fast too.
public class MyObject
{
public string name { get; set; }
public string plaintext { get; set; }
public string group { get; set; }
public string description { get; set; }
}

It's annoying when APIs do things like this (using numbers as property names), but all is not lost. Simply deserialize the JSON using Json.NET and then access each of the items using the indexer operator on the parent object.
EDIT:
I almost never create DTOs when deserializing JSON. It's lots of unnecessary boilerplate in most cases. I prefer deserializing to a dynamic object, but that won't be as effective when dealing with property names that begin with digits.
Here is how I would deserialize your sample message:
using System;
using Newtonsoft.Json;
using Newtonsoft.Json.Linq;
namespace JsonExample
{
internal class Program
{
private static void Main()
{
const string json = #"
{
'1001': {
'name': 'Boots of Speed',
'plaintext': 'Slightly increases Movement Speed',
'group': 'BootsNormal',
'description': '<...'
}
}";
var jObject = JsonConvert.DeserializeObject<JObject>(json);
var plaintext = jObject["1001"]["plaintext"].Value<string>();
Console.WriteLine(plaintext);
}
}
}

When put into http://JSONLint.com,
{
"1001": {
"name": "Boots of Speed",
"plaintext": "Slightly increases Movement Speed",
"group": "BootsNormal",
"description": "<..."
}
}
Validates as JSON.