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UWP C# - How to deserialize JsonObject into a class using Windows.Data.Json?

I don't want to use Newtonsoft's Json.Net library. I'm avoiding any third-party dependencies if I can help it in this project.
If I have JSON that looks like this:
{
"has_more_items": false,
"items_html": "...",
"min_position": "1029839231781429248"
}
and I have a class that looks like this:
public class TwitterJson
{
bool hasMore { get; set; } // has_more_items
string rawText { get; set; } // items_html
string nextKey { get; set; } // min_position
}
and I have a JsonObject containing the above JSON:
JsonObject theJson = JsonObject.Parse(result);
How do I deserialize the JsonObject into my class? I've been trying to find a clear example of this, and everything I've found uses Json.Net.

I've been trying to find a clear example of this, and everything I've found uses Json.Net.
Because reinventing existing functionality is a waste of time especially when all the hard work has already been done for you.
If you insist on not using it then you will have to manually construct the object model based on the expected JSON.
For example, assuming publicly available properties
public class TwitterJson {
public bool hasMore { get; set; } // has_more_items
public string rawText { get; set; } // items_html
public string nextKey { get; set; } // min_position
}
Then parsing the above to the desired object model
JsonObject theJson = JsonObject.Parse(result);
var model = new TwitterJson {
hasMore = theJson.GetNamedBoolean("has_more_items"),
rawText = theJson.GetNamedString("items_html"),
nextKey = theJson.GetNamedString("min_position")
};

As mentioned by #Dimith, you need to decorate your class with [DataContract] and [DateMember], Please refer to below code which will convert your JSON into a given object.
// Deserialize a JSON string to a given object.
public static T ReadToObject<T>(string json) where T: class, new()
{
DataContractJsonSerializer ser = new DataContractJsonSerializer(typeof(T));
using (MemoryStream stream = new MemoryStream(Encoding.UTF8.GetBytes(json)))
{
return ser.ReadObject(stream) as T;
}
}
Class:
[DataContract]
public class TwitterJson
{
[DataMember(Name = "has_more_items")]
bool hasMore { get; set; } // has_more_items
[DataMember(Name = "items_html")]
string rawText { get; set; } // items_html
[DataMember(Name = "min_position")]
string nextKey { get; set; } // min_position
}
Sample on how to use:
var result = "{\"has_more_items\": false, \"items_html\": \"...\",\"min_position\": \"1029839231781429248\"}";
var obj = ReadToObject<TwitterJson>(result);

You have to decorate your class with [DataContract] and [DataMember] attributes. Write the json into a memory stream and deserialize using DataContractJsonSerializer
Here is a more elaborated sample.
In addition to #Nkosi's answer below are some Comparisons between JSON.net and other alternatives:
JSON.Net vs DataContractJsonSerializer
JSON.Net vs Windows.Data.Json

JSON change value

I have a JSON value like this
{"$id":"649271776","$type":"outdoorgame","Overs":50,"Balls":6,"TeamName":"TestTeam"}
I wrote a C# code like this to change the value of Overs from 50 to 10
var jsonString = sSession.GameState; //this is the value {"$id":"649271776","$type":"outdoorgame","Overs":50,"Balls":6,"TeamName":"TestTeam"}
dynamic jsonObject =
Newtonsoft.Json.JsonConvert.DeserializeObject(jsonString);
jsonObject.Overs = 10;
var modifiedJsonString = Newtonsoft.Json.JsonConvert.SerializeObject(jsonObject);
This code is changing the value of Overs from 50 to 10. The problem I am facing when I use the above code modifiedJsonString is missing these two values
"$id":"649271776","$type":"outdoorgame"
giving the output as {Overs":10,"Balls":6,"TeamName":"TestTeam"} I want $id and $type also in the modifiedJsonString.
I want modifiedJsonString like this {"$id":"649271776","$type":"outdoorgame","Overs":10,"Balls":6,"TeamName":"TestTeam"}
Can anyone tell me how to solve this problem

The problem is that $id and $type are not valid identifiers, and can't appear as members of the returned dynamic object built by the JSON serializer. As in gldraphael's answer, the solution is to create your own concrete class to hold the deserialized object; for the properties whose names start with $ you'll need to use JsonPropertyAttribute to remap the names:
public class GameState
{
[JsonProperty("$id")] public string ID { get; set; }
[JsonProperty("$type")] public string Type { get; set; }
int Overs { get; set; }
int Balls { get; set; }
public string TeamName { get; set; }
}
Further, Json.NET treats $type as a special property name and this interferes with proper deserialization of your object. To get around this, we must use the MetadataPropertyHandling.Ignore serializer setting.
Thus you can deserialize, modify and re-serialize like this:
string jsonString = "{\"$id\":\"649271776\",\"$type\":\"outdoorgame\",\"Overs\":50,\"Balls\":6,\"TeamName\":\"TestTeam\"}";
JsonSerializerSettings settings = new JsonSerializerSettings() { MetadataPropertyHandling = MetadataPropertyHandling.Ignore };
GameState jsonObject = JsonConvert.DeserializeObject<GameState>(jsonString, settings);
jsonObject.Overs = 10;
var modifiedJsonString = JsonConvert.SerializeObject(jsonObject);
See it in action.

You can use JToken to handle this.
using Newtonsoft.Json;
using Newtonsoft.Json.Linq;
var jsonString = "{\"$id\":\"649271776\",\"$type\":\"outdoorgame\",\"Overs\":50,\"Balls\":6,\"TeamName\":\"TestTeam\"}";
JToken jsonObject = JToken.Parse(jsonString);
jsonObject["Overs"] = 10;
var modifiedJsonString = JsonConvert.SerializeObject(jsonObject);
// In case one wanted to update the $type and $id fields
jsonObject["$type"] = "asdf";
jsonObject["$id"] = 123456;
var modifiedJsonString2 = JsonConvert.SerializeObject(jsonObject);
Will result in:
modifiedJsonString --> {"$id":"649271776","$type":"outdoorgame","Overs":10,"Balls":6,"TeamName":"TestTeam"}
And if you needed to update $id and $type, that is possible, too.
modifiedJsonString2 -->
{"$id":123456,"$type":"asdf","Overs":10,"Balls":6,"TeamName":"TestTeam"}
Demo on .NET Fiddle: https://dotnetfiddle.net/a370Mv

Use a concrete class. You'll need to annotate the fields with $ prefixes manually. Eg:
public class Example
{
public string Field { get; set; }
[JsonProperty("$type")]
public string Type { get; set; }
}
Here's a working example.
In your case the class will look something like:
public class ObjName
{
[JsonProperty("$id")]
public string Id { get; set; }
[JsonProperty("$type")]
public string Type { get; set; }
public int Overs { get; set; }
public int Balls { get; set; }
public string TeamName { get; set; }
}
(Just be mindful of the property case).

How to deserialize specific element with DataContractJsonSerializer

I'm trying to deserialize json data with DataContractJsonSerializer class. a problem is how to set root element?
my json data is here.
{
"delete":{
"status":{
"id":696142765093072896,
"id_str":"696142765093072896",
"user_id":2223183576,
"user_id_str":"2223183576"
},
"timestamp_ms":"1454808363540"
}
}
and I wrote class for deserialization like this. but it isn't works. my Status always null.
[DataContract(Name="delete")]
public class Delete
{
[DataMember(Name="status")]
public DeletedStatus Status { get; set; }
}
public class DeletedStatus
{
[DataMember(Name = "id")]
public long Id { get; set; }
[DataMember(Name = "user_id")]
public long UserId { get; set; }
}
how can I start parse json from specific element?

Based on what I can tell from the JSON, the deserialization appears to be failing because the root property of the object is the "delete" property. I don't believe this will work with the DataContractJsonSerializer simply because the given type will not match the Delete type. One other possible issue is that I see the DeleteStatus class is missing a [DataContract] attribute.
Long story short, there is no simple way of doing what you want to do. That being said, there is a short and sweet way of deserializing the JSON without adding a lot of extra headache. I suggest creating a data type that represents the JSON in its current state, and deserialize to that type instead.
I wrote a Unit Test that you can run from a Visual Studio test project. I hope this helps.
JsonDeserializationTests.cs
using Microsoft.VisualStudio.TestTools.UnitTesting;
using System.Runtime.Serialization.Json;
using System.IO;
namespace SerializationTests {
[TestClass]
public class JsonDeserializationTests {
[TestMethod]
public void Deserialize_Delete_Type_Success() {
string json = string.Empty;
//Set the DataContractJsonSerializer target type to our wrapper type.
var ser = new DataContractJsonSerializer(typeof(DeleteWrapperJsonResult));
//Create an instance of the wrapper that reflects the JSON that you gave.
//This will help me mock the data that you gave.
var deleteWrapper = new DeleteWrapperJsonResult {
delete = new DeleteJsonResult {
status = new DeletedStatusJsonResult {
id = 696142765093072896,
user_id = 2223183576
}
}
};
//Convert the mock data to JSON to reflect the JSON that you gave.
using (var serStream = new MemoryStream()) {
using (var sr = new StreamReader(serStream)) {
ser.WriteObject(serStream, deleteWrapper);
serStream.Position = 0;
json = sr.ReadToEnd(); //Set the JSON string here.
//Output "{\"delete\":{\"status\":{\"id\":696142765093072896,\"id_str\":\"696142765093072896\",\"user_id\":2223183576,\"user_id_str\":\"2223183576\"}}}"
}
}
//Prepeare to Deserialize the JSON.
var deserialized = default(DeleteWrapperJsonResult);
using (var deserStream = new MemoryStream()) {
using (var sw = new StreamWriter(deserStream)) {
sw.Write(json); //Write the JSON to the MemoryStream
sw.Flush();
deserStream.Seek(0, SeekOrigin.Begin);
//Deserialize the JSON into an instance of our wrapper class.
//This works because of the structure of the JSON.
deserialized = (DeleteWrapperJsonResult)ser.ReadObject(deserStream);
}
}
//Initialize the actual Delete instanace with what was deserialized.
var delete = new Delete {
Status = new DeletedStatus {
//These values were populated with the JSON values.
UserId = deserialized.delete.status.user_id,
Id = deserialized.delete.status.id
}
};
//Write asserts around what was given and check for equality.
Assert.AreEqual(delete.Status.UserId, deleteWrapper.delete.status.user_id);
Assert.AreEqual(delete.Status.Id, deleteWrapper.delete.status.id);
//Test Passes for Me
}
}
}
Delete.cs
using System.Runtime.Serialization;
namespace SerializationTests {
[DataContract]
[KnownType(typeof(Delete))]
public class Delete {
[DataMember]
public DeletedStatus Status { get; set; }
}
[DataContract]
[KnownType(typeof(DeletedStatus))]
public class DeletedStatus {
[DataMember]
public long Id { get; set; }
[DataMember]
public long UserId { get; set; }
}
/**************************************************************
These types below are what comprise our wrapper class so that we can
use the JSON in its current state. The wrapper classes have properties that
are synonymous with the JSON properties.
**************************************************************/
//This structure represents the object nesting as it appears currently in your example.
[DataContract]
[KnownType(typeof(DeleteJsonResult))]
public class DeleteWrapperJsonResult {
[DataMember]
public DeleteJsonResult delete { get; set; }
}
[DataContract]
[KnownType(typeof(DeleteJsonResult))]
public class DeleteJsonResult {
[DataMember]
public DeletedStatusJsonResult status { get; set; }
}
[DataContract]
[KnownType(typeof(DeletedStatusJsonResult))]
public class DeletedStatusJsonResult {
[DataMember]
public long id { get; set; }
[DataMember]
public string id_str {
get {
return id.ToString();
}
set {
return;
}
}
[DataMember]
public long user_id { get; set; }
[DataMember]
public string user_id_str {
get {
return user_id.ToString();
}
set {
return;
}
}
}
}
As of the time of this writing, my unit test is passing! Let me know if I can assist further.

Pains deserializing C# JSON string

I am trying to post some data to my MVC 3 controller through a hidden text field that contains some JSON. I have that JSON passed in via string coursesList. Anyone have an idea why this is not working?
All I'm doing is making a byte [] out of the JSON string, writing it to a MemoryStream, and deserializing that stream -- or, attempting to. BookCourse bc always ends up with null properties.
Here's something like the JSON I would be using:
[{"coursesection":"1234","netlogon":"jsmith","label":"CRSE-1313 Generic Course Titling ~ Joe Smith"}]
And here's the object to be deserialized into:
using System.Runtime.Serialization;
namespace xxxx.Models
{
[DataContract]
public class BookCourse
{
[DataMember]
public string coursesection { get; set; }
[DataMember]
public string netlogon { get; set; }
[DataMember]
public string label { get; set; }
}
}
Finally, the controller action code to do it --
var byteArray = Encoding.ASCII.GetBytes(coursesList);
// Deserialize byte array to data type
var stream = new MemoryStream();
stream.Write(byteArray, 0, byteArray.Length);
var crs = new DataContractJsonSerializer(typeof(BookCourse));
stream.Position = 0;
// Read stream to object
ad.CourseSectionIDs = new List<int>();
try
{
var bc = (BookCourse) crs.ReadObject(stream);
while (bc.coursesection != null)
{
cs.AssociateCourseBook(bc.netlogon, bc.coursesection, ad.ISBN);
bc = (BookCourse)crs.ReadObject(stream);
}
}
catch (System.Runtime.Serialization.SerializationException e)
{
// Is this best practice for handling "none"?
}

Your JSON string represents a collection of BookCourse, not a single BookCourse. So adapt your code:
var serializer = new DataContractJsonSerializer(typeof(BookCourse[]));
and then:
var bookCourses = (BookCourse[])crs.ReadObject(stream);
or if you want to work with a single BookCourse you will need to change your JSON string and remove the wrapping square brackets which represent a collection.

Darin is correct, here is the change if you want to do it on a contract level.
[DataContract]
public class BookCourse
{
[DataMember]
public string coursesection { get; set; }
[DataMember]
public string netlogon { get; set; }
[DataMember]
public string label { get; set; }
}
[DataContract]
public class BookCourceCollection
{
[DataMember]
public List<BookCourse> Collection;
public static BookCourceCollection ReturnCollection(string jsonString)
{
MemoryStream ms;
BookCourceCollection collection;
using (ms = new MemoryStream(Encoding.UTF8.GetBytes(jsonString)))
{
DataContractJsonSerializer ser = new DataContractJsonSerializer(typeof(BookCourceCollection));
collection = ser.ReadObject(ms) as BookCourceCollection;
}
return collection;
}
}
Usage:
string jsonString = "Your JSON string from the front end";
var bookCourceObject = BookCourseCollection.ReturnCollection(jsonString);
foreach (BookCourse bookCourse in bookCourceObject.Collection)
{
cs.AssociateCourseBook(bookCourse.netlogon, bookCourse.coursesection, bookCourse.ISBN);
}

Deserialization of a json string returns null values

This is the JSON string -
"{\"body\":[\"VAL1\",\"VAL2\"],\"head\":{\"result\":true,\"time\":3.859}}"
These are my classes -
[Serializable]
public class ResponseHead
{
public bool result {get; set;}
public float time {get; set;}
}
[Serializable]
public class ResponseBody
{
public string[] body {get; set;}
}
[Serializable]
public class ResponseObj
{
public ResponseBody body {get; set;}
public ResponseHead head { get; set; }
}
And the code -
JavaScriptSerializer serializer = new JavaScriptSerializer();
using (var streamReader = new StreamReader(httpResponse.GetResponseStream()))
{
responseText = streamReader.ReadToEnd();
}
ResponseObj response_obj = new ResponseObj();
ResponseHead rhead = new ResponseHead();
rhead = serializer.Deserialize<ResponseHead>(responseText); //not working
The resultant ResponseHead object has values:
result: false
time: 0.0
It is not able to map the values correctly, but i'm not sure why. The ResponseBody values are coming in correctly.
Please help!

Looks like you are trying to read ResponseObj (which is top level object in your JSON), but coded for ResponseHead. Following should work:
var wholeObject = serializer.Deserialize<ResponseObj>(responseText);
rhead = wholeObject.head;