I need to deserialize a JSON string into a type which is not know at compile time. There are several classes that it can be deserialized into. The name of the class is provided as input into the application and based on that I want to instantiate the class (already done this through reflection):
var type = Type.GetType(className);
var myClassInstance = (IParser)Activator.CreateInstance(type);
...and then use its type as the generic type parameter for JsonConvert.DeserializeObject<typeof(myClassInstance).Name>(jsonString) but that doesn't work.
How can I provide the class to DeserializeObject<>() dynamically?
Instead of using an generic method overload like JsonConvert.DeserializeObject<T>(String) and having to resort to reflection as some comments state, you could simply use the non generic counterpart JsonConvert.DeserializeObject(String, Type), which just takes in a Type instance like you already have!
Implementation
Initialization
var class1s = new Class1() {
ID = 1, Name = "Test", Comment = "This Code is Tested!."
};
var class2s = new Class2() {
xVal1 = 1, XVal2 = 5, xval3 = 10
};
var JSON1 = Newtonsoft.Json.JsonConvert.SerializeObject(class1s);
var JSON2 = Newtonsoft.Json.JsonConvert.SerializeObject(class2s);
Calling Functions
var classname1 = typeof(Class1).FullName;
var type1 = Type.GetType(classname1);
var classname2 = typeof(Class2).FullName;
var type2 = Type.GetType(classname2);
var c = LocalConverter(JSON1, type1);
var c2 = LocalConverter(JSON2, type2);
Class Models
public class Class1 {
public int ID {
get;
set;
}
public string Name {
get;
set;
}
public string Comment {
get;
set;
}
}
public class Class2 {
public int xVal1 {
get;
set;
}
public int XVal2 {
get;
set;
}
public int xval3 {
get;
set;
}
}
Required Method
private object LocalConverter(string o, Type xtype) {
return Newtonsoft.Json.JsonConvert.DeserializeObject(o, xtype);
}
I am trying to deserialize JSON file and want to assign to object ScanResult. var text showing all the values but scanresult showing null some null values. https://gyazo.com/ff2ce386f845394c458a88d43a1f30d8
please suggest if I am missing something.
//MY jSon File SCAN Test 1-1543045410222.json 's code
{
"at": 1543045410222,
"i": 1000,
"s": {
"Sensor1": ["OFF"],
"Sensor2": ["OFF"],
"DataReady1": ["OFF"],
"DataReady2": ["OFF"],
"CV1": [5.0],
"CV2": [6.0]
}
}
//ViewModel Code is as below:
public void ResendScanResult()
{
var ScanActivities = scanActivityManager.GetAll();
foreach (var item in ScanActivities)
{
var scanName = item.ScanName;
var dir = _dataFilePath + scanName + "\\";
var jsonFileName = string.Format("{0}{1}-{2}.json", dir, scanName, item.ScanDateEpoch);
string fileName = Path.GetFileName(jsonFileName);
// ScanResult scanResult = new ScanResult();
var text = File.ReadAllText(jsonFileName);
//var scanResults = JsonConvert.DeserializeObject<ScanResult>(text);
Common.Model.ScanResult scanResult = JsonConvert.DeserializeObject<Common.Model.ScanResult>(text);
var Mvm = MonitorViewModel.Instance;
// TargetProvider target = Mvm.GetTargetProvider(scanResult);
// Mvm.PublishToServer(target, scanResult);
}
}
and my scanRescult class code is as below :
namespace ABX.Common.Model
{
public class ScanResult
{
public ScanResult()
{
At = DateTimeOffset.Now.ToUnixTimeMilliseconds();
Interval = 1;
}
public string Name { get; set; }
public long At { get; set; }
public long Interval { get; set; }
public JObject Values { get; set; }
public string FileName { get; set; }
public JObject ToJson()
{
JObject json = new JObject
{
{ "at", At },
{ "i", Interval },
{ "s", Values }
};
return json;
}
Either rename your class properties to match your JSON, rename your JSON to match your class properties, or implement a custom JsonConverter, where you can implement arbitrary mapping.
I am trying to create a JSON string which contains one container and one array.
I can do this by using a stringbuilder but I am trying to find a better way to get the JSON string; I want:
{ "message":{ "text":"test sms"},"endpoints":["+9101234"]}
I tried this:
string json = new JavaScriptSerializer().Serialize(new
{
text = "test sms",
endpoints = "[dsdsd]"
});
And the output is:
{"text":"test sms","endpoints":"[dsdsd]"}
Any help or suggestions how to get the required format?
In the most recent version of .NET we have the System.Text.Json namespace, making third party libraries unecessary to deal with json.
using System.Text.Json;
And use the JsonSerializer class to serialize:
var data = GetData();
var json = JsonSerializer.Serialize(data);
and deserialize:
public class Person
{
public string Name { get; set; }
}
...
var person = JsonSerializer.Deserialize<Person>("{\"Name\": \"John\"}");
Other versions of .NET platform there are different ways like the JavaScriptSerializer where the simplest way to do this is using anonymous types, for sample:
string json = new JavaScriptSerializer().Serialize(new
{
message = new { text = "test sms" },
endpoints = new [] {"dsdsd", "abc", "123"}
});
Alternatively, you can define a class to hold these values and serialize an object of this class into a json string. For sample, define the classes:
public class SmsDto
{
public MessageDto message { get; set; }
public List<string> endpoints { get; set; }
}
public class MessageDto
{
public string text { get; set; }
}
And use it:
var sms = new SmsDto()
{
message = new MessageDto() { text = "test sms" } ,
endpoints = new List<string>() { "dsdsd", "abc", "123" }
}
string json = new JavaScriptSerializer().Serialize(sms);
Error: The type arguments for method 'System.Web.Script.Serialization.JavaScriptSerializer.Deserialize<T>(string)' cannot be inferred from the usage. Try specifying the type arguments explicitly.
string url = null;
public int GetLinkedIn()
{
var jsonString = new System.Net.WebClient().DownloadString("http://www.linkedin.com/countserv/count/share?url=" + url + "&format=json");
var json = new JavaScriptSerializer().Deserialize<dictionary dynamic="" string="">>(jsonString);
var count = Convert.ToInt32(json["count"]);
return count;
}
You can use JavaScriptSerializer class to resolve the Json response
int GetLinkedIn(string url)
{
url = "http://www.linkedin.com/countserv/count/share?url=" + url + "&format=json";
var jsonString = new WebClient().DownloadString(url);
return new JavaScriptSerializer().Deserialize<LinkdInJson>(jsonString).count;
}
And you need to create a class to represent the entity of the Json response
public class LinkdInJson
{
public int count { get; set; }
public string fCnt { get; set; }
public string fCntPlusOne { get; set; }
public string url { get; set; }
}
The type argument to the Deserialize method is wrong, the correct form is
var dic = new JavaScriptSerializer().Deserialize<Dictionary<string, dynamic>>(jsonString);
What's the difference between JsonConvert.DeserializeObject and JObject.Parse? As far as I can tell, both take a string and are in the Json.NET library. What kind of situation would make one more convenient than the other, or is it mainly just preference?
For reference, here's an example of me using both to do exactly the same thing - parse a Json string and return a list of one of the Json attributes.
public ActionResult ReadJson()
{
string countiesJson = "{'Everything':[{'county_name':null,'description':null,'feat_class':'Civil','feature_id':'36865',"
+"'fips_class':'H1','fips_county_cd':'1','full_county_name':null,'link_title':null,'url':'http://www.alachuacounty.us/','name':'Alachua County'"+ ",'primary_latitude':'29.7','primary_longitude':'-82.33','state_abbreviation':'FL','state_name':'Florida'},"+
"{'county_name':null,'description':null,"+ "'feat_class':'Civil','feature_id':'36866','fips_class':'H1','fips_county_cd':'3','full_county_name':null,'link_title':null,'url':'http://www.bakercountyfl.org/','name':'Baker County','primary_latitude':'30.33','primary_longitude':'-82.29','state_abbreviation':'FL','state_name':'Florida'}]}";
//Can use either JSONParseObject or JSONParseDynamic here
List<string> counties = JSONParseObject(countiesJson);
JSONParseDynamic(countiesJson);
return View(counties);
}
public List<string> JSONParseObject(string jsonText)
{
JObject jResults = JObject.Parse(jsonText);
List<string> counties = new List<string>();
foreach (var county in jResults["Everything"])
{
counties.Add((string)county["name"]);
}
return counties;
}
public List<string> JSONParseDynamic(string jsonText)
{
dynamic jResults = JsonConvert.DeserializeObject(jsonText);
List<string> counties = new List<string>();
foreach(var county in jResults.Everything)
{
counties.Add((string)county.name);
}
return counties;
}
The LINQ-to-JSON API (JObject, JToken, etc.) exists to allow working with JSON without needing to know its structure ahead of time. You can deserialize any arbitrary JSON using JToken.Parse, then examine and manipulate its contents using other JToken methods. LINQ-to-JSON also works well if you just need one or two values from the JSON (such as the name of a county).
JsonConvert.DeserializeObject, on the other hand, is mainly intended to be used when you DO know the structure of the JSON ahead of time and you want to deserialize into strongly typed classes. For example, here's how you would get the full set of county data from your JSON into a list of County objects.
class Program
{
static void Main(string[] args)
{
string countiesJson = "{'Everything':[{'county_name':null,'description':null,'feat_class':'Civil','feature_id':'36865',"
+"'fips_class':'H1','fips_county_cd':'1','full_county_name':null,'link_title':null,'url':'http://www.alachuacounty.us/','name':'Alachua County'"+ ",'primary_latitude':'29.7','primary_longitude':'-82.33','state_abbreviation':'FL','state_name':'Florida'},"+
"{'county_name':null,'description':null,"+ "'feat_class':'Civil','feature_id':'36866','fips_class':'H1','fips_county_cd':'3','full_county_name':null,'link_title':null,'url':'http://www.bakercountyfl.org/','name':'Baker County','primary_latitude':'30.33','primary_longitude':'-82.29','state_abbreviation':'FL','state_name':'Florida'}]}";
foreach (County c in JsonParseCounties(countiesJson))
{
Console.WriteLine(string.Format("{0}, {1} ({2},{3})", c.name,
c.state_abbreviation, c.primary_latitude, c.primary_longitude));
}
}
public static List<County> JsonParseCounties(string jsonText)
{
return JsonConvert.DeserializeObject<RootObject>(jsonText).Counties;
}
}
public class RootObject
{
[JsonProperty("Everything")]
public List<County> Counties { get; set; }
}
public class County
{
public string county_name { get; set; }
public string description { get; set; }
public string feat_class { get; set; }
public string feature_id { get; set; }
public string fips_class { get; set; }
public string fips_county_cd { get; set; }
public string full_county_name { get; set; }
public string link_title { get; set; }
public string url { get; set; }
public string name { get; set; }
public string primary_latitude { get; set; }
public string primary_longitude { get; set; }
public string state_abbreviation { get; set; }
public string state_name { get; set; }
}
Notice that Json.Net uses the type argument given to the JsonConvert.DeserializeObject method to determine what type of object to create.
Of course, if you don't specify a type when you call DeserializeObject, or you use object or dynamic, then Json.Net has no choice but to deserialize into a JObject. (You can see for yourself that your dynamic variable actually holds a JObject by checking jResults.GetType().FullName.) So in that case, there's not much difference between JsonConvert.DeserializeObject and JToken.Parse; either will give you the same result.
JsonConvert.DeserializeObject has one advantage over JObject.Parse:
It is possible to use custom JsonSerializerSettings.
This can be very useful e.g. if you want to control how dates are deserialized.
By default dates are deserialized into DateTime objects.
This means that you may end up with a date with another time zone than the one in the json string.
You can change this behaviour by creating a JsonSerializerSetting and setting
DateParseHandling to DateParseHandling.DateTimeOffset.
An example:
var json = #"{ ""Time"": ""2015-10-28T14:05:22.0091621+00:00""}";
Console.WriteLine(json);
// Result: { "Time": "2015-10-28T14:05:22.0091621+00:00" }
var jObject1 = JObject.Parse(json);
Console.WriteLine(jObject1.ToString());
// Result: { "Time": "2015-10-28T15:05:22.0091621+01:00" }
var jObject2 = Newtonsoft.Json.JsonConvert.DeserializeObject(json,
new Newtonsoft.Json.JsonSerializerSettings
{
DateParseHandling = Newtonsoft.Json.DateParseHandling.DateTimeOffset
});
Console.WriteLine(jObject2.ToString());
// Result: { "Time": "2015-10-28T14:05:22.0091621+00:00" }
For me the key difference I was interested in was Speed.
I made a simple test to find out if it was faster to use JToken.Parse(string) or DeserializeObject<JToken>(string) to create a large amount of JToken and these were the results after 2,000,000 iterations using a sample of real world data
Method
Operating System Ticks
Milliseconds
JsonConvert
86123945
8612ms
JToken
67671724
6767ms
There was some variation between runs but the difference was always large.
Here is the test so you can modify it or run it yourself:
private static string s = #"{'stream':'btcusdt #bookTicker','data':{'u':20430107433,'s':'BTCUSDT','b':'21223.72000000','B':'3.29440000','a':'21223.73000000','A':'2.05450000'}}";
private static Stopwatch sw = new Stopwatch();
private static void Main(string[] args)
{
JToken convert = default;
sw.Restart();
for (int i = 0; i < 2000000; i++)
{
convert = JsonConvert.DeserializeObject<JToken>(s);
}
Console.WriteLine("JsonConvert: " + sw.ElapsedTicks + " [" + sw.ElapsedMilliseconds + "ms]");
convert.ToString();
convert = default;
sw.Restart();
for (int i = 0; i < 2000000; i++)
{
convert = JToken.Parse(s);
}
Console.WriteLine("JToken : " + sw.ElapsedTicks + " [" + sw.ElapsedMilliseconds + "ms]");
convert.ToString();
Console.ReadLine();
}
I knew an advantage that JsonConvert.DeserializeObject can deserialize an Array/List json text directly, but JObject cannot.
Try below sample code:
using Newtonsoft.Json;
using Newtonsoft.Json.Linq;
using System;
using System.Collections.Generic;
namespace NetCoreJsonNETDemo
{
internal class Person
{
[JsonProperty]
internal string Name
{
get;
set;
}
[JsonProperty]
internal int? Age
{
get;
set;
}
}
internal class PersonContainer
{
public List<Person> Persons
{
get;
set;
}
}
class Program
{
static T RecoverPersonsWithJsonConvert<T>(string json)
{
return JsonConvert.DeserializeObject<T>(json);
}
static T RecoverPersonsWithJObejct<T>(string json) where T : class
{
try
{
return JObject.Parse(json).ToObject<T>();
}
catch (Exception ex)
{
Console.WriteLine("JObject threw an Exception: " + ex.Message);
return null;
}
}
static void Main(string[] args)
{
List<Person> persons = new List<Person>();
persons.Add(new Person()
{
Name = "Jack",
Age = 18
});
persons.Add(new Person()
{
Name = "Sam",
Age = null
});
persons.Add(new Person()
{
Name = "Bob",
Age = 36
});
string json = JsonConvert.SerializeObject(persons, new JsonSerializerSettings()
{
Formatting = Formatting.Indented
});
List<Person> newPersons = RecoverPersonsWithJsonConvert<List<Person>>(json);
newPersons = RecoverPersonsWithJObejct<List<Person>>(json);//JObject will throw an error, since the json text is an array.
PersonContainer personContainer = new PersonContainer()
{
Persons = persons
};
json = JsonConvert.SerializeObject(personContainer, new JsonSerializerSettings()
{
Formatting = Formatting.Indented
});
newPersons = RecoverPersonsWithJObejct<PersonContainer>(json).Persons;
newPersons = null;
newPersons = RecoverPersonsWithJsonConvert<PersonContainer>(json).Persons;
Console.WriteLine("Press any key to end...");
Console.ReadKey();
}
}
}
Apart from the answers provided here around usage, which are correct as per me :
Jobject.Parse -> when the Json is not strongly Typed or you do not know the structure of Json ahead of time
JsonConvert.DeserializeObject<T> -> When you know which class or type to cast the Json in. T can be a complex class or a simple type
My answer is based on the performance in case where the structure is not known, as given in the OP code, if we benchmark the usage of both methods for performance, it is observed that Jobject.Parse() fares well in terms of allocated memory, please ignore the name of methods, I am first calling the method with 'JsonConvert.DeserializeObject' and then second method is with Jobject.Parse