Develop Reference

How can I parse json to a C# object (Class)?

I have JSON data that I need to parse from C# object.
this is JSON Example.
{
"types":
[
[
"tour_type",
[
["groups",1],
["individual",2]
]
]
]
}
Here are my C# classes that are meant to contain that data:
using System;
using Newtonsoft.Json;
namespace JsonDeserializationTest
{
[JsonProperty("types")]
public class Types
{
[JsonProperty]
public List<Type> Values {get;set;}
}
public class Type
{
[JsonProperty]
public string Key {get;set;}
[JsonProperty]
public List<Dictionary<string, int>> Values { get; set; }
}
}
It's not working now.
How can I fix it?

Use the JsonSerializer (System.Text.Json) object.
Code:
YourClass obj = JsonSerializer.Deserialize<YourClass>(jsonString);

Your json has a list of list of the object... but you are declaring only List of the object.
public class Types
{
[JsonProperty("types")]
public List<List<object>> Values { get; set; }
// ------ UPDATE: This can only be list of list of 'object' ------- \\
}
Also, you are using the JsonProperty on the class, which is not where that normally goes. You want to use that on the property of the class.
UPDATE:
You cannot use List<List<Type>> for the json you are getting, it can only be List<List<object>>. You have to use object because it can either be a string or a List<List<string>>. After you update your Types class, you can successfully deserialize the json above.
var obj = JsonConvert.DeserializeObject<Types>(json);
and based on your json definition, you can access tour_type by using the following code
types.Values.First()[0].ToString()
// output: tour_type
List<List<string>> data = JsonConvert.DeserializeObject<List<List<string>>>(types.Values.First()[1].ToString())
// data[0]
[0]: "groups"
[1]: "1"
// data[1]
[0]: "individual"
[1]: "2"
Since both of the items in the types are objects, you will either have to convert them to string or a list of list of strings or whatever object they actually are.

The JSON payload in the provided example is formatted quite strangely, especially since it contains seemingly unnecessary array nesting. A payload like this usually includes more nested objects (rather than a bunch of nested arrays). Additionally, it has a list of (string, int) pairs, which is semantically very similar to a Dictionary<string, int>, but the payload doesn't lend itself to that. It would be helpful to know where it is coming from (what context) to understand how it might change.
The example JSON brings up a few questions (that you may want to ask yourself):
Can the "types" array contain multiple entries (at its immediate nesting)?
Can the "tour_type" key name appear after the array of string, int pairs? Is it possible for an entry where no such name exists?
What other elements can exist in the arrays within "tour_type"?
Is it guaranteed that the most nested array will contain just a single (string, int) pair?
Similarly, it is hard to understand what the example C# class is trying to encapsulate. Is List<Dictionary<string, int>> necessary?
All that said, here's a solution using the built-in System.Text.Json library, that could work for you. You could write something similar using Newtonsoft.Json, if necessary. The solution assumes:
We can't change the JSON payload (and that the third party API response will always returns something that is structurally similar to the example)
We can only make minimal changes to the C# class object provided in the example
The solution creates and a JsonConverter<T> that uses the low-level Utf8JsonReader to manually parse and create the custom object. This is required since nested "[" are being used to delineate what should be objects rather than "{". The converter is then registered by annotating the class with the attribute. Now, simply call JsonSerializer.Deserialize, passing in the JSON payload.
public class Tours
{
[JsonPropertyName("types")]
public List<UserType> Types { get; set; }
}
// Annotate the type to register the converter to use
[JsonConverter(typeof(CustomUserTypeConverter))]
public class UserType
{
public string Key { get; set; }
public Dictionary<string, int> Values { get; set; }
}
// This will use the low-level reader to build up the UserType
public class CustomUserTypeConverter : JsonConverter<UserType>
{
// Extra structural validation was done for invalid/incomplete JSON
// which might be too strict or incorrect and hence might require adjustments.
public override UserType Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
{
var result = new UserType();
if (!reader.Read())
{
throw new JsonException("Incomplete JSON.");
}
if (reader.TokenType != JsonTokenType.EndArray)
{
result.Key = reader.GetString();
ReadAndValidate(ref reader, JsonTokenType.StartArray);
int depthSnapshot = reader.CurrentDepth;
var values = new Dictionary<string, int>();
do
{
reader.Read();
if (reader.TokenType != JsonTokenType.StartArray && reader.TokenType != JsonTokenType.EndArray)
{
throw new JsonException($"Invalid JSON payload. Expected Start or End Array. TokenType: {reader.TokenType}, Depth: {reader.CurrentDepth}.");
}
if (reader.CurrentDepth <= depthSnapshot)
{
break;
}
reader.Read();
if (reader.TokenType != JsonTokenType.EndArray)
{
string key = reader.GetString();
reader.Read();
int value = reader.GetInt32();
values.Add(key, value);
ReadAndValidate(ref reader, JsonTokenType.EndArray);
}
} while (true);
ReadAndValidate(ref reader, JsonTokenType.EndArray);
result.Values = values;
}
return result;
}
private void ReadAndValidate(ref Utf8JsonReader reader, JsonTokenType expectedTokenType)
{
bool readNext = reader.Read();
if (!readNext || reader.TokenType != expectedTokenType)
{
string message = readNext ?
$"Invalid JSON payload. TokenType: {reader.TokenType}, Depth: {reader.CurrentDepth}, Expected: {expectedTokenType}" :
$"Incomplete JSON. Expected: {expectedTokenType}";
throw new JsonException(message);
}
}
// Implement this method if you need to Serialize (i.e. write) the object
// back to JSON
public override void Write(Utf8JsonWriter writer, UserType value, JsonSerializerOptions options)
{
throw new NotImplementedException();
}
}
Here's how you would use the above converter to serialize the JSON string provided in the example, along with how to access the values.
public static Tours ParseJson(string json)
{
Tours tours = JsonSerializer.Deserialize<Tours>(json);
return tours;
}
public static void AccessValues(Tours tours)
{
foreach (UserType data in tours.Types)
{
string typeName = data.Key; // "tour_type"
foreach (KeyValuePair<string, int> pairs in data.Values)
{
string key = pairs.Key; // "groups" or "individual
int value = pairs.Value; // 1 or 2
}
}
}
For what it's worth, Visual Studio suggests the following C# class structure for the example JSON (which is similar to what #Jawad suggested):
public class Rootobject
{
public object[][] types { get; set; }
}
Hope that helps.

I couldn't figure out your JSON so I created an example with verified JSON.
Try this:
JSON:
{
"Items": [
{
"Name": "tour",
"Attributes": [
{
"Name": "groups",
"Value": 1
},
{
"Name": "individual",
"Value": 2
}
]
},
{
"Name": "demo",
"Attributes": [
{
"Name": "this is demo",
"Value": 3
},
{
"Name": "design pattern",
"Value": 99
}
]
}
]
}
Types foo = JsonSerializer.Deserialize<Types>(jsonString);
public class TypeAttribute
{
public string Name { get; set; }
public int Value { get; set; }
}
public class Type
{
private readonly ICollection<TypeAttribute> _attributes;
public Type()
{
_attributes = new Collection<TypeAttribute>();
}
public void AddAttributes(IEnumerable<TypeAttribute> attrs)
{
foreach(TypeAttribute ta in attrs)
{
_attributes.Add(ta);
}
}
public string Name { get; set; }
public IEnumerable<TypeAttribute> Attributes
{
get { return _attributes; }
set
{
foreach(TypeAttribute ta in value)
{
_attributes.Add(ta);
}
}
}
}
public class Types
{
ICollection<Type> _items;
public Types()
{
_items = new Collection<Type>();
}
public void AddItems(IEnumerable<Type> tps)
{
foreach (Type t in tps)
{
_items.Add(t);
}
}
public IEnumerable<Type> Items
{
get { return _items; }
set
{
foreach (Type t in value)
{
_items.Add(t);
}
}
}
}

JsonUtility in Unity is not working anymore. Why?

I'm trying to get a integer value from a Json that I GET from a server. I used JsonUtility from Unity libreries and It was working fine. And suddenly it is not parsing anymore.
All values returned are Null.
//SAMPLE CODE
SpinResult res = JsonUtility.FromJson<SpinResult>(download.downloadHandler.text);
spinValue = res.result;
//spinValue is always 0. It was working fine
//CLASS
[System.Serializable]
public class SpinResult
{
public int result;
}
//JSON
{
"data": {
"type": "",
"id": "",
"attributes": {
"server_seed": "",
"client_seed": "",
"result": 31,
},
"next_spin": {
"hashed_server_seed": "",
"client_seed": ""
}
}
}
I just need the integer "RESULT", in this case it should be 31 but the actual output is always 0. I check the Json everytime and its working perfectly fine.

I have not tested this, but try making your class look like this:
[System.Serializable]
public class SpinResult
{
public string type;
public string id;
public Attributes attributes;
}
[System.Serializable]
public class Attributes
{
public string server_seed;
public string client_seed;
public int result;
}
Then to get the value of result you would use:
int spinValue = res.attributes.result;

Deserialize JSON value without name

How can I deserialize a string in C# that only have values and no name. It looks like this: The problem is that this stream of string does not have name and uses array.
{
"result": {
"14400": [
[
1502985600,
262.18,
262.18,
257,
257,
1096.0131
],
[
1503000000,
257,
261.33,
254.8,
257,
1130.5897
]
],
"14405": [
[
1503014400,
258.03,
261.5,
257.01,
257.01,
520.7805
],
[
1503028800,
258,
260.98,
252.4,
259.56,
298.5658
],
]
]
}
}

Just create a class like
public class Root
{
public Dictionary<int,List<List<double>>> Result { get; set; }
}
and deserialize as
var res = JsonConvert.DeserializeObject<Root>(json);

I see it's an array, you could create a method to parse the class out of given JArray.
The Jason data
public void methpod()
{
string json ="Your jason value "
var factory = new Factory();
var suggest = factory.Create(json);
Console.WriteLine(suggest);
}
Make a class as suggested :
public class Factory
{
public Evan Create(string json)
{
var array = JArray.Parse(json);
string search = array[0].ToString();
string[] terms = array[1].ToArray().Select(item => item.ToString()).ToArray();
return new Evan{Search = search, Terms = terms};
}
}
and another
public class Evan
{
public string Search { get; set; }
public IEnumerable<string> Terms { get; set; }
public override string ToString()
{
return string.Format("Search={0},Terms=[{1}]",
Search, string.Join(",", Terms));
}
}

Tip
If you have JSON that you want to deserialize, and you don't have the class to deserialize it into, Visual Studio 2019 can automatically generate the class you need:
Copy the JSON that you need to deserialize.
Create a class file and delete the template code.
Choose Edit > Paste Special > Paste JSON as Classes.
The result is a class that you can use for your deserialization target

Serialize and deserialize part of JSON object as string with WCF

I have a WCF REST service which has a resource which contains several typed fields, and then a field which can be an array of objects. I want the field on our service to serialize this field as if it were a string. Example:
[DataContract]
public class User
{
[DataMember]
public long ID;
[DataMember]
public string Logon;
[DataMember]
public string Features;
}
When users of our API POST a new User object, I'd like them to be able to do use something like this as the body:
{
"ID" : 123434,
"Logon" : "MyLogon",
"Features" : [
{ "type": "bigFeature", "size": 234, "display":true },
{ "type": "smFeature", "windowCount": 234, "enableTallness": true}
]
}
instead of
{
"ID" : 123434,
"Logon" : "MyLogon",
"Features" : "[
{ \"type\": \"bigFeature\", \"size\": 234, \"display\":true },
{ \"type\": \"smFeature\", \"windowCount\": 234, \"enableTallness\": true}
]"
}
On the service side, I'm going to be saving the "Features" array as JSON text blog in the database, and when I return the Object on GET calls, I'd like it to round trip properly.

If you were willing to switch to Json.NET, you could serialize your Features string as a private JToken proxy property:
[DataContract]
public class User
{
[DataMember]
public long ID;
[DataMember]
public string Logon;
string _features = null;
[IgnoreDataMember]
public string Features
{
get
{
return _features;
}
set
{
if (value == null)
_features = null;
else
{
JToken.Parse(value); // Throws an exception on invalid JSON.
_features = value;
}
}
}
[DataMember(Name="Features")]
JToken FeaturesJson
{
get
{
if (Features == null)
return null;
return JToken.Parse(Features);
}
set
{
if (value == null)
Features = null;
else
Features = value.ToString(Formatting.Indented); // Or Formatting.None, if you prefer.
}
}
}
Note that, in order to serialize the Features string without escaping, it must be valid JSON, otherwise your outer JSON will be corrupt. I enforce this in the setter. You could use JArray instead of JToken to enforce the requirement that the string represent a JSON array, if you prefer.
Note that the string formatting isn't preserved during serialization.

AOP Logging with custom arguments

Before every method executes, I want to log all parameters from that method. For that, I would use AOP (Aspect oriented programming) and create a "Loggable" attribute. But... I also would like to know the content of my parameters. For a string-parameter, that's not a problem. But I would like to know a good solution for every occasion, like objects, ints, doubles,...
Is there any other way to solve this other then to overwrite the ToString() method?
(in examples I always came across a string parameter...)
Example:
public class MyType {
public int Id { get; set; }
public string Name { get; set; }
public double Value { get; set; }
}
[Loggable]
public void IDoWhateverIWant(MyType data, int count, string message){
//Whatever I want
}
IDoWhateverIWant(
new MyType(){
Id = 1,
Name = "My test data name",
Value = 1234.56}
, 5
, "Log me, please");
Logmessage (the way these parameters are presented are the same to me, I just want to see them):
22/07/2014 9:30 Incoming message: IDoWhateverIWant with parameters:
- data : Id = 1
Name = "My test data name"
Value = 1234.56
- count: 5
- message: "Log me, please"

A simple option is to use NewtonSoft.Json to serialize each parameter. This simple example:
public void IDoWhateverIWant(MyType data, int count, string message)
{
string logMessage =
ParameterValueMessage(data, "data") + Environment.NewLine +
ParameterValueMessage(count, "count") + Environment.NewLine +
ParameterValueMessage(message, "message");
Debug.Print(logMessage);
}
public static string ParameterValueMessage<T>(T arg, string name)
{
string result = JsonConvert.SerializeObject(arg, Formatting.Indented);
return name + ": " + result;
}
Produces the following:
data: {
"Id": 1,
"Name": "My test data name",
"Value": 1234.56
}
count: 5
message: "Log me, please"
My own preference though is for each method to take a single parameter object - the logging code is a lot neater and more generic with parameter objects and all of the individual parameter names can be inferred from the parameter object:
public class MyParameterObject
{
public MyType data { get; set; }
public int count { get; set; }
public string message { get; set; }
}
which is serialized in much the same way and has the benefit of not having to pass in the name of every individual parameter:
public void IAlsoDoWhateverIWant(MyParameterObject parameterObject)
{
string logMessage = ParameterValueMessage(parameterObject);
Debug.Print(logMessage);
}
public static string ParameterValueMessage<T>(T arg)
{
return JsonConvert.SerializeObject(arg, Formatting.Indented);
}
and produces the following output:
{
"data": {
"Id": 1,
"Name": "My test data name",
"Value": 1234.56
},
"count": 5,
"message": "Log me, please"
}