I've got the following json document:
{
"name": "bert",
"Bikes": {
"Bike1": {
"value": 1000,
"type": "Trek"
},
"Bike2": {
"value": 2000,
"type": "Canyon"
}
}
}
With potentially other bikes like Bike3...BikeN. I want to deserialize to C# objects. Problem is that in the deserialization step the bikes data is completely lost, resulting in a null Bikes collection.
Code to reproduce:
[Test]
public void FirstCityJsonParsingTest()
{
var file = #"./testdata/test.json";
var json = File.ReadAllText(file);
var res = JsonConvert.DeserializeObject<Person>(json);
Assert.IsTrue(res.Name == "bert");
// next line is failing, because res.Bikes is null...
Assert.IsTrue(res.Bikes.Count == 2);
}
public class Bike
{
public string Id { get; set; }
public int Value { get; set; }
public string Type { get; set; }
}
public class Person
{
public string Name { get; set; }
public List<Bike> Bikes { get; set; }
}
To fix this problem a change in the used model is necessary. But what change is needed here to fill the bikes data correctly?
Note: Changing the input document is not an option (as it's a spec)
Your code structure is not reflecting your json. Common approach to deserializing json with dynamic property names is to use Dictionary<string, ...> (supported both by Json.NET and System.Text.Json). Try the following:
public class Bike
{
public int Value { get; set; }
public string Type { get; set; }
}
public class Person
{
public string Id { get; set; }
public string Name { get; set; }
public Dictionary<string, Bike> Bikes { get; set; }
}
Person.Bikes should be changed to Dictionary<string, Bike> (also Bike.Id property is not needed) cause Bikes json element is not an array but object.
Related
I am using this code to read a json file firstSession.json and display it on a label.
var assembly = typeof(ScenarioPage).GetTypeInfo().Assembly;
string jsonFileName = "firstSession.json";
Stream stream = assembly.GetManifestResourceStream($"{assembly.GetName().Name}.{jsonFileName}");
using (var reader = new StreamReader(stream))
{
var json = reader.ReadToEnd(); //json string
var data = JsonConvert.DeserializeObject<SessionModel>(json);
foreach (SessionModel scenario in data)
{
scenarioName.Text = scenario.title;
break;
}
scenarioName.Text = data.title; // scenarioName is the name of the label
}
SessionModel.cs looks like:
public class SessionModel : IEnumerable
{
public int block { get; set; }
public string name { get; set; }
public string title { get; set; }
public int numberMissing { get; set; }
public string word1 { get; set; }
public string word2 { get; set; }
public string statement1 { get; set; }
public string statement2 { get; set; }
public string question { get; set; }
public string positive { get; set; } // positive answer (yes or no)
public string negative { get; set; } // negative answer (yes or no)
public string answer { get; set; } // positive or negative
public string type { get; set; }
public string format { get; set; }
public string immersion { get; set; }
public IEnumerator GetEnumerator()
{
throw new NotImplementedException();
}
}
The beginning of my json is:
{
"firstSession": [
{
"block": 1,
"name": "mark",
"title": "mark's house",
"numberMissing": 1,
"word1": "distracted",
"word2": "None",
"statement1": "string 1",
"statement2": "None",
"question": "question",
"positive": "No",
"negative": "Yes",
"answer": "Positive",
"type": "Social",
"format": "Visual",
"immersion": "picture"
},
I am getting a Newtonsoft.Json.JsonSerializationException: Cannot deserialize the current JSON object into type "MyProject.SessionModel" because the type requires a JSON array to deserialize correctly. To fix this error either change the JSON to a JSON array or change the deserialized type so that it is a normal .NET type 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. JsonObjectAttribute can also be added to the type to force it to deserialize from a JSON object. Path 'firstSession', line 2, position 17.
How can I convert the json string to a json array? Or make one of the other modifications the debugger suggests?
you need to create a wrapper class (json2csharp.com will help you do this)
public class Root {
public List<SessionModel> firstSession { get; set; }
}
then
var data = JsonConvert.DeserializeObject<Root>(json);
data.firstSession will be a List<SessionModel>
Create a new Class and have firstSession as List of SessionModel.
public class Sessions
{
public List<SessionModel> firstSession { get; set; }
}
Remove IEnumerable from the SessionModel
public class SessionModel
{
public int block { get; set; }
public string name { get; set; }
public string title { get; set; }
}
Change thedeserialization part as follows
var data = JsonConvert.DeserializeObject(line);
foreach (SessionModel scenario in data.firstSession)
{
//Here you can get each sessionModel object
Console.WriteLine(scenario.answer);
}
I'm having difficulties figuring out how to deserialize a json, that has a dynamic property (for example - UserRequest::567) the property name can be any value and the UserRequest object contains other json properties that are of interest to me
I tired writing a class and I don't know what to do with that property. What are the best practices for coping with a problem like this?
{
"objects": {
"UserRequest::567": {
"code": 0,
"message": "created",
"class": "UserRequest",
"key": "567",
"fields": {
"ref": "R-000567",
"org_id": "4"
}
}
}
}
The question is what are the best practices to read through this kind of a json string?
Thank you
To Deserialize this using Newtonsoft.Json, here are the classes:
public class CreateRequest
{
public long code { get;set; }
public string message { get; set; }
[JsonProperty("class")]
public string class1 { get; set; }
public string key { get; set; }
public Fields fields { get; set; }
}
public class Fields
{
[JsonProperty("ref")]
public string refe { get; set; }
public string org_id { get; set; }
}
public class Root
{
public Dictionary<string, CreateRequest> objects { get; set; }
//The 'string' key in the dictionary is the 'UserRequest::567'
}
Then to Deserialize use:
var x = Newtonsoft.Json.JsonConvert.DeserializeObject<Root>(jsonObject).objects.Values;
I've got the following json document:
{
"name": "bert",
"Bikes": {
"Bike1": {
"value": 1000,
"type": "Trek"
},
"Bike2": {
"value": 2000,
"type": "Canyon"
}
}
}
With potentially other bikes like Bike3...BikeN. I want to deserialize to C# objects. Problem is that in the deserialization step the bikes data is completely lost, resulting in a null Bikes collection.
Code to reproduce:
[Test]
public void FirstCityJsonParsingTest()
{
var file = #"./testdata/test.json";
var json = File.ReadAllText(file);
var res = JsonConvert.DeserializeObject<Person>(json);
Assert.IsTrue(res.Name == "bert");
// next line is failing, because res.Bikes is null...
Assert.IsTrue(res.Bikes.Count == 2);
}
public class Bike
{
public string Id { get; set; }
public int Value { get; set; }
public string Type { get; set; }
}
public class Person
{
public string Name { get; set; }
public List<Bike> Bikes { get; set; }
}
To fix this problem a change in the used model is necessary. But what change is needed here to fill the bikes data correctly?
Note: Changing the input document is not an option (as it's a spec)
Your code structure is not reflecting your json. Common approach to deserializing json with dynamic property names is to use Dictionary<string, ...> (supported both by Json.NET and System.Text.Json). Try the following:
public class Bike
{
public int Value { get; set; }
public string Type { get; set; }
}
public class Person
{
public string Id { get; set; }
public string Name { get; set; }
public Dictionary<string, Bike> Bikes { get; set; }
}
Person.Bikes should be changed to Dictionary<string, Bike> (also Bike.Id property is not needed) cause Bikes json element is not an array but object.
I am trying to deserialise some JSON that I get back from an API so that I can loop through an array of county names and add the information to a datatable in C#. However I am receiving following error at the first hurdle when I try and deserialise it:
error: System.MissingMethodException: No parameterless constructor defined for type of 'DPDJSONLibrary.DPD_JSON+LOCR_Data[]'.
The provider of the API provides an example of the JSON response as follows:
{
"error": null,
"data":[{
"country": [{
"countryCode":"GB",
"countryName":"United Kingdom",
"internalCode":"UK",
"isEUCountry":false,
"isLiabilityAllowed":false,
"isoCode":"826",
"isPostcodeRequired":false,
"liabilityMax":15000
}]
}]
}
A sample of the JSON data I am getting back from the API is:
{
"data": {
"country":[
{
"countryCode":"PM",
"countryName":"St Pierre & Miquilon",
"isoCode":"666",
"isEUCountry":false,
"isLiabilityAllowed":true,
"liabilityMax":15000,
"isPostcodeRequired":true
},
{
"countryCode":"SR",
"countryName":"Suriname",
"isoCode":"740",
"isEUCountry":false,
"isLiabilityAllowed":true,
"liabilityMax":15000,
"isPostcodeRequired":true
},
{
"countryCode":"SZ",
"countryName":"Swaziland",
"isoCode":"748",
"isEUCountry":false,
"isLiabilityAllowed":true,
"liabilityMax":15000,
"isPostcodeRequired":true
}
]
}
}
I have tried to make some classes to put the JSON in as follows:
/// <summary>
/// List Of Countries Response object.
/// </summary>
public class LOCR
{
public LOCR_Error error { get; set; }
public LOCR_Data[] data { get; set; }
}
public class LOCR_Error
{
public string errorAction { get; set; }
public string errorCode { get; set; }
public string errorMessage { get; set; }
public string errorObj { get; set; }
public string errorType { get; set; }
}
public class LOCR_Data
{
public LOCR_Data_Country[] country { get; set; }
}
public class LOCR_Data_Country
{
public string countryCode { get; set; }
public string countryName { get; set; }
public string internalCode { get; set; }
public bool isEUCountry { get; set; }
public bool isLiabilityAllowed { get; set; }
public string isoCode { get; set; }
public bool isPostcodeRequired { get; set; }
public int liabilityMax { get; set; }
}
When I get the JSON back as a string, I am trying to use the Newtonsoft (plugin?) to put it into my classes using:
JavaScriptSerializer ser = new JavaScriptSerializer();
DPD_JSON.LOCR DPDCountries = new DPD_JSON.LOCR();
DPDCountries = ser.Deserialize<DPD_JSON.LOCR>(data);
It is the last line above that is generating the error. I suspect I've written my classes wrong that I am trying to deserialise the JSON in to - can anyone see where I've gone wrong?
Deserialize will return a list and not an array, So your LOCR_Data_Country should be of type List and not array:
public class LOCR_Data
{
public List<LOCR_Data_Country> country { get; set; }
}
There's a HUGE difference between the two example JSON strings you've shown. Mainly the first one is an array : "data":[ ... ] and the second one is an object "data:{ ... }. These two are not interchangeable so you have to stick to either one of those. If the thing you're getting back from the API is an object instead you should rewrite your model to be :
public class LOCR
{
public LOCR_Error error { get; set; }
// object here since "data": { ... }
public LOCR_Data data { get; set; }
}
And as you move further with the JSON you can see that LOCR_Data.country is in fact an array in both cases "country": [ ... ] so you can stick with the current implementation of LOCR_Data class.
Try Using :
YourResultClass object = JsonConvert.DeserializeObject<YourResultClass>(Jsonstring);
See the answer of this Using JsonConvert.DeserializeObject to deserialize Json
OR
dynamic data = Json.Decode(json);
You can refer this Deserialize JSON into C# dynamic object? for further assistance
i have a web service that returns a Json string.
my problem is that i have difficulties to read it
i tried with:
JavaScriptSerializer jsSerializer = new JavaScriptSerializer();
string jsonData = reader.ReadToEnd();
var myobj = jsSerializer.Deserialize<List<CinfoRichiesta>>(jsonData);
but how can i get values from "students" and "locations"?
with javascript i used :" var j = jQuery.parseJSON(msg.d);" but i think with c# code would be different
this is an example of string:
{"Questions":{
"id":"2",
"BOOK":"3",
"students":{
"class":"3",
"theme","43"
},
"locations":{
"h":"0",
"L":"3"
}
}
}
First off, your JSON isn't valid so thats the first problem you have. You can verify this at http://jsonlint.com/ for example.
i have currently fixed this in the following way:
{
"Questions": {
"id": "2",
"BOOK": "3",
"students": {
"class": "3",
"theme": "na",
"43": "na"
},
"locations": {
"h": "0",
"L": "3"
}
}
}
Second your class should be correct, with the current JSON this should look something like this
public class Rootobject
{
public Questions Questions { get; set; }
}
public class Questions
{
public string id { get; set; }
public string BOOK { get; set; }
public Students students { get; set; }
public Locations locations { get; set; }
}
public class Students
{
public string _class { get; set; }
public string theme { get; set; }
public string _43 { get; set; }
}
public class Locations
{
public string h { get; set; }
public string L { get; set; }
}
After this you can deserialize it like this
var myobj = jsSerializer.Deserialize<List<Rootobject>>(jsonData);
And then you can get the information like this
myobj.Questions.students._class
You're deserializing to a collection of type CinfoRichiesta, which should hold a property value for students and locations.
Assuming that your JSON is correctly formatted and your class definition is suitable for the response (I recommend double checking it by pasting the entire response string into json2csharp.com)
Once that's all validated, you should be able to see the students and locations collections internally like so:
foreach(Question q in myobj)
{
Console.WriteLine(q.students.class)
}
which should give you the result of 3.
edit
I think your main question is why you're unable to access the properties of students and locations. Make sure Students is its own class as such:
public class Students
{
public int class { get; set; }
public int theme { get; set; }
}
and your locations class should be:
public class Locations
{
public int h { get; set; }
public int l { get; set; }
}
You should then have a questions class that instaniates both students and locations, as such:
public class Questions
{
public int id { get; set; }
public int book { get; set; }
public Student students { get; set; }
public Locations locations { get; set; }
}
When working with JSON deserialization, it's important that your object property names (ie class) match the response string in terms of case. So If you wrote it as public int Theme, it won't directly map.
Slightly annoying in terms of coding standards, but hey ho :-)