Given following json result:
The default json result has a known set of fields:
{
"id": "7908",
"name": "product name"
}
But can be extended with additional fields (in this example _unknown_field_name_1 and _unknown_field_name_2) of which the names are not known when requesting the result.
{
"id": "7908",
"name": "product name",
"_unknown_field_name_1": "some value",
"_unknown_field_name_2": "some value"
}
I would like the json result to be serialized and deserialized to and from a class with properties for the known fields and map the unknown fields (for which there are no properties) to a property (or multiple properties) like a dictionary so they can be accessed and modified.
public class Product
{
public string id { get; set; }
public string name { get; set; }
public Dictionary<string, string> fields { get; set; }
}
I think I need a way to plug into a json serializer and do the mapping for the missing members myself (both for serialize and deserialize).
I have been looking at various possibilities:
json.net and custom contract resolvers (can't figure out how to do it)
datacontract serializer (can only override onserialized, onserializing)
serialize to dynamic and do custom mapping (this might work, but seems a lot of work)
let product inheriting from DynamicObject (serializers work with reflection and do not invoke the trygetmember and trysetmember methods)
I'm using restsharp, but any serializer can be plugged in.
Oh, and I cannot change the json result, and this or this didn't help me either.
Update:
This looks more like it: http://geekswithblogs.net/DavidHoerster/archive/2011/07/26/json.net-custom-convertersndasha-quick-tour.aspx
An even easier option to tackling this problem would be to use the JsonExtensionDataAttribute from JSON .NET
public class MyClass
{
// known field
public decimal TaxRate { get; set; }
// extra fields
[JsonExtensionData]
private IDictionary<string, JToken> _extraStuff;
}
There's a sample of this on the project blog here
UPDATE Please note this requires JSON .NET v5 release 5 and above
See https://gist.github.com/LodewijkSioen/5101814
What you were looking for was a custom JsonConverter
This is a way you could solve it, although I don't like it that much. I solved it using Newton/JSON.Net. I suppose you could use the JsonConverter for deserialization aswell.
private const string Json = "{\"id\":7908,\"name\":\"product name\",\"_unknown_field_name_1\":\"some value\",\"_unknown_field_name_2\":\"some value\"}";
[TestMethod]
public void TestDeserializeUnknownMembers()
{
var #object = JObject.Parse(Json);
var serializer = new Newtonsoft.Json.JsonSerializer();
serializer.MissingMemberHandling = Newtonsoft.Json.MissingMemberHandling.Error;
serializer.Error += (sender, eventArgs) =>
{
var contract = eventArgs.CurrentObject as Contract ?? new Contract();
contract.UnknownValues.Add(eventArgs.ErrorContext.Member.ToString(), #object[eventArgs.ErrorContext.Member.ToString()].Value<string>());
eventArgs.ErrorContext.Handled = true;
};
using (MemoryStream memoryStream = new MemoryStream(Encoding.UTF8.GetBytes(Json)))
using (StreamReader streamReader = new StreamReader(memoryStream))
using (JsonReader jsonReader = new JsonTextReader(streamReader))
{
var result = serializer.Deserialize<Contract>(jsonReader);
Assert.IsTrue(result.UnknownValues.ContainsKey("_unknown_field_name_1"));
Assert.IsTrue(result.UnknownValues.ContainsKey("_unknown_field_name_2"));
}
}
[TestMethod]
public void TestSerializeUnknownMembers()
{
var deserializedObject = new Contract
{
id = 7908,
name = "product name",
UnknownValues = new Dictionary<string, string>
{
{"_unknown_field_name_1", "some value"},
{"_unknown_field_name_2", "some value"}
}
};
var json = JsonConvert.SerializeObject(deserializedObject, new DictionaryConverter());
Console.WriteLine(Json);
Console.WriteLine(json);
Assert.AreEqual(Json, json);
}
}
class DictionaryConverter : JsonConverter
{
public DictionaryConverter()
{
}
public override bool CanConvert(Type objectType)
{
return objectType == typeof(Contract);
}
public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
{
throw new NotImplementedException();
}
public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
{
var contract = value as Contract;
var json = JsonConvert.SerializeObject(value);
var dictArray = String.Join(",", contract.UnknownValues.Select(pair => "\"" + pair.Key + "\":\"" + pair.Value + "\""));
json = json.Substring(0, json.Length - 1) + "," + dictArray + "}";
writer.WriteRaw(json);
}
}
class Contract
{
public Contract()
{
UnknownValues = new Dictionary<string, string>();
}
public int id { get; set; }
public string name { get; set; }
[JsonIgnore]
public Dictionary<string, string> UnknownValues { get; set; }
}
}
I thought I'd throw my hat in the ring since I had a similar problem recently. Here's an example of the JSON I wanted to deserialize:
{
"agencyId": "agency1",
"overrides": {
"assumption.discount.rates": "value: 0.07",
".plan": {
"plan1": {
"assumption.payroll.growth": "value: 0.03",
"provision.eeContrib.rate": "value: 0.35"
},
"plan2": {
".classAndTier": {
"misc:tier1": {
"provision.eeContrib.rate": "value: 0.4"
},
"misc:tier2": {
"provision.eeContrib.rate": "value: 0.375"
}
}
}
}
}
}
This is for a system where overrides apply at different levels and are inherited down the tree. In any case, the data model I wanted was something that would allow me to have a property bag with these special inheritance rules also supplied.
What I ended up with was the following:
public class TestDataModel
{
public string AgencyId;
public int Years;
public PropertyBagModel Overrides;
}
public class ParticipantFilterModel
{
public string[] ClassAndTier;
public string[] BargainingUnit;
public string[] Department;
}
public class PropertyBagModel
{
[JsonExtensionData]
private readonly Dictionary<string, JToken> _extensionData = new Dictionary<string, JToken>();
[JsonIgnore]
public readonly Dictionary<string, string> Values = new Dictionary<string, string>();
[JsonProperty(".plan", NullValueHandling = NullValueHandling.Ignore)]
public Dictionary<string, PropertyBagModel> ByPlan;
[JsonProperty(".classAndTier", NullValueHandling = NullValueHandling.Ignore)]
public Dictionary<string, PropertyBagModel> ByClassAndTier;
[JsonProperty(".bargainingUnit", NullValueHandling = NullValueHandling.Ignore)]
public Dictionary<string, PropertyBagModel> ByBarginingUnit;
[OnSerializing]
private void OnSerializing(StreamingContext context)
{
foreach (var kvp in Values)
_extensionData.Add(kvp.Key, kvp.Value);
}
[OnSerialized]
private void OnSerialized(StreamingContext context)
{
_extensionData.Clear();
}
[OnDeserialized]
private void OnDeserialized(StreamingContext context)
{
Values.Clear();
foreach (var kvp in _extensionData.Where(x => x.Value.Type == JTokenType.String))
Values.Add(kvp.Key, kvp.Value.Value<string>());
_extensionData.Clear();
}
}
The basic idea is this:
The PropertyBagModel on deserialization by JSON.NET has the ByPlan, ByClassAndTier, etc. fields populated and also has the private _extensionData field populated.
Then JSON.NET calls the private OnDeserialized() method and that will move the data from _extensionData to Values as appropriate (or drop it on the floor otherwise - presumably you could log this if it was something you wanted to know). We then remove the extra gunk from _extensionData so it doesn't consume memory.
On serialization, the OnSerializing method gets calls where we move stuff into _extensionData so it gets saved.
When serialization has finished, OnSerialized gets called and we remove the extra stuff from _extensionData.
We could further delete and recreate the _extensionData Dictionary when needed but I didn't see a real value in this as I'm not using tons of these objects. To do this we'd just create on OnSerializing and delete on OnSerialized. On OnDeserializing, instead of clearing, we could free it.
I was looking into a similar issue and found this post.
Here is a way to do it using reflection.
To make it more generic, one should check the type of the property instead of simply using ToString() in propertyInfo.SetValue, unless OFC all the actual properties are strings.
Also, lowercase property names is not standard in C# but given that GetProperty is case sensitive there are few other options.
public class Product
{
private Type _type;
public Product()
{
fields = new Dictionary<string, object>();
_type = GetType();
}
public string id { get; set; }
public string name { get; set; }
public Dictionary<string, object> fields { get; set; }
public void SetProperty(string key, object value)
{
var propertyInfo = _type.GetProperty(key);
if (null == propertyInfo)
{
fields.Add(key,value);
return;
}
propertyInfo.SetValue(this, value.ToString());
}
}
...
private const string JsonTest = "{\"id\":7908,\"name\":\"product name\",\"_unknown_field_name_1\":\"some value\",\"_unknown_field_name_2\":\"some value\"}";
var product = new Product();
var data = JObject.Parse(JsonTest);
foreach (var item in data)
{
product.SetProperty(item.Key, item.Value);
}
Related
I have an API that returns a JSON object from a MongoDB in which one of the properties is an "open-ended" document, meaning it can be any valid JSON for that property. I don't know what the names of the properties are ahead of time, they can be any string. I only know that this particular property needs to be serialized exactly how it is stored in the database. So if the property name that was originally stored was "Someproperty", the serialized response in JSON needs to be "Someproperty", NOT "someProperty".
We have this configuration:
ContractResolver = new CamelCasePropertyNamesContractResolver();
in our CustomJsonSerializer, but it is messing with the formatting of the response when returning the "open ended" JSON. It is camel-casing all of these properties when in fact we want the response to be exactly how they are stored in MongoDB (BSON). I know the values are maintaining their case when storing/retrieving via the database, so that is not the issue.
How can I tell JSON.net to essentially bypass the CamelCasePropertyNameResolver for all of the child properties of a particular data point?
EDIT:
Just to give a bit more info, and share what I have already tried:
I thought about overriding the PropertyNameResolver like so:
protected override string ResolvePropertyName(string propertyName)
{
if (propertyName.ToLower().Equals("somedocument"))
{
return propertyName;
}
else return base.ResolvePropertyName(propertyName);
}
However, if I have a JSON structure like this:
{
"Name" : "MyObject",
"DateCreated" : "11/14/2016",
"SomeDocument" :
{
"MyFirstProperty" : "foo",
"mysecondPROPERTY" : "bar",
"another_random_subdoc" :
{
"evenmoredata" : "morestuff"
}
}
}
then I would need all of the properties any child properties' names to remain exactly as is. The above override I posted would (I believe) only ignore on an exact match to "somedocument", and would still camelcase all of the child properties.
What you can do is, for the property in question, create a custom JsonConverter that serializes the property value in question using a different JsonSerializer created with a different contract resolver, like so:
public class AlternateContractResolverConverter : JsonConverter
{
[ThreadStatic]
static Stack<Type> contractResolverTypeStack;
static Stack<Type> ContractResolverTypeStack { get { return contractResolverTypeStack = (contractResolverTypeStack ?? new Stack<Type>()); } }
readonly IContractResolver resolver;
JsonSerializerSettings ExtractAndOverrideSettings(JsonSerializer serializer)
{
var settings = serializer.ExtractSettings();
settings.ContractResolver = resolver;
settings.CheckAdditionalContent = false;
if (settings.PreserveReferencesHandling != PreserveReferencesHandling.None)
{
// Log an error throw an exception?
Debug.WriteLine(string.Format("PreserveReferencesHandling.{0} not supported", serializer.PreserveReferencesHandling));
}
return settings;
}
public AlternateContractResolverConverter(Type resolverType)
{
if (resolverType == null)
throw new ArgumentNullException("resolverType");
resolver = (IContractResolver)Activator.CreateInstance(resolverType);
if (resolver == null)
throw new ArgumentNullException(string.Format("Resolver type {0} not found", resolverType));
}
public override bool CanRead { get { return ContractResolverTypeStack.Count == 0 || ContractResolverTypeStack.Peek() != resolver.GetType(); } }
public override bool CanWrite { get { return ContractResolverTypeStack.Count == 0 || ContractResolverTypeStack.Peek() != resolver.GetType(); } }
public override bool CanConvert(Type objectType)
{
throw new NotImplementedException("This contract resolver is intended to be applied directly with [JsonConverter(typeof(AlternateContractResolverConverter), typeof(SomeContractResolver))] or [JsonProperty(ItemConverterType = typeof(AlternateContractResolverConverter), ItemConverterParameters = ...)]");
}
public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
{
using (ContractResolverTypeStack.PushUsing(resolver.GetType()))
return JsonSerializer.CreateDefault(ExtractAndOverrideSettings(serializer)).Deserialize(reader, objectType);
}
public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
{
using (ContractResolverTypeStack.PushUsing(resolver.GetType()))
JsonSerializer.CreateDefault(ExtractAndOverrideSettings(serializer)).Serialize(writer, value);
}
}
internal static class JsonSerializerExtensions
{
public static JsonSerializerSettings ExtractSettings(this JsonSerializer serializer)
{
// There is no built-in API to extract the settings from a JsonSerializer back into JsonSerializerSettings,
// so we have to fake it here.
if (serializer == null)
throw new ArgumentNullException("serializer");
var settings = new JsonSerializerSettings
{
CheckAdditionalContent = serializer.CheckAdditionalContent,
ConstructorHandling = serializer.ConstructorHandling,
ContractResolver = serializer.ContractResolver,
Converters = serializer.Converters,
Context = serializer.Context,
Culture = serializer.Culture,
DateFormatHandling = serializer.DateFormatHandling,
DateFormatString = serializer.DateFormatString,
DateParseHandling = serializer.DateParseHandling,
DateTimeZoneHandling = serializer.DateTimeZoneHandling,
DefaultValueHandling = serializer.DefaultValueHandling,
EqualityComparer = serializer.EqualityComparer,
// No Get access to the error event, so it cannot be copied.
// Error = += serializer.Error
FloatFormatHandling = serializer.FloatFormatHandling,
FloatParseHandling = serializer.FloatParseHandling,
Formatting = serializer.Formatting,
MaxDepth = serializer.MaxDepth,
MetadataPropertyHandling = serializer.MetadataPropertyHandling,
MissingMemberHandling = serializer.MissingMemberHandling,
NullValueHandling = serializer.NullValueHandling,
ObjectCreationHandling = serializer.ObjectCreationHandling,
ReferenceLoopHandling = serializer.ReferenceLoopHandling,
// Copying the reference resolver doesn't work in the default case, since the
// actual BidirectionalDictionary<string, object> mappings are held in the
// JsonSerializerInternalBase.
// See https://github.com/JamesNK/Newtonsoft.Json/blob/master/Src/Newtonsoft.Json/Serialization/DefaultReferenceResolver.cs
ReferenceResolverProvider = () => serializer.ReferenceResolver,
PreserveReferencesHandling = serializer.PreserveReferencesHandling,
StringEscapeHandling = serializer.StringEscapeHandling,
TraceWriter = serializer.TraceWriter,
TypeNameHandling = serializer.TypeNameHandling,
// Changes in Json.NET 10.0.1
//TypeNameAssemblyFormat was obsoleted and replaced with TypeNameAssemblyFormatHandling in Json.NET 10.0.1
//TypeNameAssemblyFormat = serializer.TypeNameAssemblyFormat,
TypeNameAssemblyFormatHandling = serializer.TypeNameAssemblyFormatHandling,
//Binder was obsoleted and replaced with SerializationBinder in Json.NET 10.0.1
//Binder = serializer.Binder,
SerializationBinder = serializer.SerializationBinder,
};
return settings;
}
}
public static class StackExtensions
{
public struct PushValue<T> : IDisposable
{
readonly Stack<T> stack;
public PushValue(T value, Stack<T> stack)
{
this.stack = stack;
stack.Push(value);
}
// By using a disposable struct we avoid the overhead of allocating and freeing an instance of a finalizable class.
public void Dispose()
{
if (stack != null)
stack.Pop();
}
}
public static PushValue<T> PushUsing<T>(this Stack<T> stack, T value)
{
if (stack == null)
throw new ArgumentNullException();
return new PushValue<T>(value, stack);
}
}
Then use it like so:
public class RootObject
{
public string Name { get; set; }
public DateTime DateCreated { get; set; }
[JsonProperty(NamingStrategyType = typeof(DefaultNamingStrategy))]
[JsonConverter(typeof(AlternateContractResolverConverter), typeof(DefaultContractResolver))]
public SomeDocument SomeDocument { get; set; }
}
public class SomeDocument
{
public string MyFirstProperty { get; set; }
public string mysecondPROPERTY { get; set; }
public AnotherRandomSubdoc another_random_subdoc { get; set; }
}
public class AnotherRandomSubdoc
{
public string evenmoredata { get; set; }
public DateTime DateCreated { get; set; }
}
(Here I am assuming you want the "SomeDocument" property name to be serialized verbatim, even though it wasn't entirely clear from your question. To do that, I'm using JsonPropertyAttribute.NamingStrategyType from Json.NET 9.0.1. If you're using an earlier version, you'll need to set the property name explicitly.)
Then the resulting JSON will be:
{
"name": "Question 40597532",
"dateCreated": "2016-11-14T05:00:00Z",
"SomeDocument": {
"MyFirstProperty": "my first property",
"mysecondPROPERTY": "my second property",
"another_random_subdoc": {
"evenmoredata": "even more data",
"DateCreated": "2016-11-14T05:00:00Z"
}
}
}
Note that this solution does NOT work well with preserving object references. If you need them to work together, you may need to consider a stack-based approach similar to the one from Json.NET serialize by depth and attribute
Demo fiddle here.
Incidentally, have you considered storing this JSON as a raw string literal, as in the answer to this question?
I think you should look at this backwards.
Instead of trying to NOT touch the properties you don't know, let that be the default behavior and touch the ones you DO know.
In other words, don't use the CamelCasePropertyNamesContractResolver. Deal with the properties you know appropriately and let the other ones pass through transparently.
I'm trying to add some data into a Json file like this but I have some error :
using System.Text.Json;
void addToJson(int myData)
{
var data = JsonSerializer.Deserialize<scoreList>(File.ReadAllText("scoreData.json"));
data.scores.Add(myData);
var jsonString = JsonSerializer.Serialize<scoreList>(data);
File.WriteAllText("scoreData.json", jsonString);
}
I think my code is good, I just have an error at : data.scores.Add(myData);
And here's my class :
class scoreTest
{
public int score { get; set; }
}
class scoreList
{
public List<scoreTest> scores { get; set; }
}
There is nothing related to JSON, you should add the proper value to the list
void addToJson(int myData)
{
//...
data.scores.Add(new scoreTest { score = myData });
//...
}
scores has List<scoreTest> type, you can't simply add int value to the list, you should create a scoreTest instance first with score value set to myData
To handle nested class deserialization/serialization use:
new JsonSerializerSettings
{
TypeNameHandling = TypeNameHandling.All
};
Try this:
void addToJson(int myData)
{
var settings = new JsonSerializerSettings
{
TypeNameHandling = TypeNameHandling.All
};
var data = JsonSerializer.Deserialize<scoreList>(File.ReadAllText("scoreData.json"), settings);
data.scores.Add(myData);
var jsonString = JsonSerializer.Serialize<scoreList>(data, settings);
File.WriteAllText("scoreData.json", jsonString);
}
It is OK, if all member's type are primitive, but if not.
You may need to constructor for a member.
This will helpful to avoid nullreference exception while deserialize.
class scoreList {
public List<scoreTest> scores { get; set; }
//We need default constructor for initialize class member.
public scoreList(){
this.scores = new List<scoreTest>();
}
}
I am serializing using Json.NET, but the resulting string ends up way too long, because it includes a ton of surplus info about the assembly that I have no use for.
For example, here is what I'm getting for one of the types:
"Assets.Logic.CompGroundType, Assembly-CSharp, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null": {
"$type": "Assets.Logic.CompGroundType, Assembly-CSharp",
"GroundType": 1,
"EntityID": 1,
"<GroundType>k__BackingField": 1
}
"GroundType" is an enum, and "EntityID" is int.
Here is my desired result:
"Assets.Logic.CompGroundType" : {
"$type": "Assets.Logic.CompGroundType",
"GroundType": 1,
"EntityID": 1,
"<GroundType>k__BackingField": 1
}
If it's possible, I would also like to remove the "$type" field while still correctly deserializing inherited types (I'm not sure why it's necessary, since that info is duplicated from one line above, but if I remove it by setting TypeNameHandling.None, I get deserialization errors for child types). I am also not sure what the last field (k__BackingField) is for.
If it's possible, I would want to reduce it even further, to:
"Assets.Logic.CompGroundType" : {
"GroundType": 1,
"EntityID": 1,
}
I understand it's possible to manually customize the serialization scheme for each type in Json.Net, but I have hundreds of types, and so I would like to do it automatically through some global setting.
I tried changing "FormatterAssemblyStyle", but there is no option for "None" there, only "Simple" or "Full", and I'm already using "Simple".
Thanks in advance for any help.
Edit:
It's important to note that the types are keys in a dictionary. That's why the type appears twice (in the first and second row of the first example).
After implementing a custom SerializationBinder, I was able to reduce the length of the "$type" field, but not the Dictionary key field. Now I get the following:
"componentDict": {
"Assets.Logic.CompGroundType, Assembly-CSharp, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null": {
"$type": "Assets.Logic.CompGroundType",
"GroundType": 1,
"EntityID": 1,
"<GroundType>k__BackingField": 1
}
}
Edit 2:
The code I'm trying to serialize is an entity component system. I'll try to provide a detailed example with code samples.
All components (including CompGroundType above) inherit from the following abstract class:
abstract class Component
{
public int EntityID { get; private set; }
protected Component(int EntityID)
{
this.EntityID = EntityID;
}
}
The issue I'm encountering is in the serialization of the Entity class' componentDict:
class Entity
{
readonly public int id;
private Dictionary<Type, Component> componentDict = new Dictionary<Type, Component>();
[JsonConstructor]
private Entity(Dictionary<Type, Component> componentDict, int id)
{
this.id = id;
this.componentDict = componentDict;
}
}
componentDict contains all the components attached to the entity. In each entry <Type, Component>, the type of the value is equal to the key.
I am doing the serialization recursively, using the following JsonSerializerSettings:
JsonSerializerSettings serializerSettings = new JsonSerializerSettings()
{
ReferenceLoopHandling = ReferenceLoopHandling.Ignore,
ContractResolver = new MyContractResolver(),
TypeNameHandling = TypeNameHandling.Auto,
SerializationBinder = new TypesWithNoAssmeblyInfoBinder(),
Formatting = Formatting.Indented
}
Where MyContractResolver is identical to the one form this answer.
TypesWithNoAssmeblyInfoBinder does the change from edit 1:
private class TypesWithNoAssmeblyInfoBinder : ISerializationBinder
{
public Type BindToType(string assemblyName, string typeName)
{
return Type.GetType(typeName);
}
public void BindToName(Type serializedType, out string assemblyName, out string typeName)
{
assemblyName = null;
typeName = serializedType.FullName;
}
}
The serialization itself is done as follows:
var jsonSerializer = JsonSerializer.Create(serializerSettings);
using (FileStream zippedFile = new FileStream(Application.persistentDataPath + fileName, FileMode.Create))
{
using (GZipStream archive = new GZipStream(zippedFile, CompressionLevel.Fastest))
{
using (StreamWriter sw = new StreamWriter(archive))
{
jsonSerializer.Serialize(sw, savedData);
}
}
}
Edit 4:
The CompGroundType class (an example of a finished component):
class CompGroundType : Component
{
public enum Type {Grass, Rock};
public Type GroundType { get; private set; }
[JsonConstructor]
private CompGroundType(Type groundType, int entityID) : base(entityID)
{
this.GroundType = groundType;
}
}
The first part is the embedded $type information which is being injected by json.net to help with deserialization later. I think this example from the documentation will do what you want.
public class KnownTypesBinder : ISerializationBinder
{
public IList<Type> KnownTypes { get; set; }
public Type BindToType(string assemblyName, string typeName)
{
return KnownTypes.SingleOrDefault(t => t.Name == typeName);
}
public void BindToName(Type serializedType, out string assemblyName, out string typeName)
{
assemblyName = null;
typeName = serializedType.Name;
}
}
public class Car
{
public string Maker { get; set; }
public string Model { get; set; }
}
KnownTypesBinder knownTypesBinder = new KnownTypesBinder
{
KnownTypes = new List<Type> { typeof(Car) }
};
Car car = new Car
{
Maker = "Ford",
Model = "Explorer"
};
string json = JsonConvert.SerializeObject(car, Formatting.Indented, new JsonSerializerSettings
{
TypeNameHandling = TypeNameHandling.Objects,
SerializationBinder = knownTypesBinder
});
Console.WriteLine(json);
// {
// "$type": "Car",
// "Maker": "Ford",
// "Model": "Explorer"
// }
object newValue = JsonConvert.DeserializeObject(json, new JsonSerializerSettings
{
TypeNameHandling = TypeNameHandling.Objects,
SerializationBinder = knownTypesBinder
});
Console.WriteLine(newValue.GetType().Name);
// Car
It just needs tweaking to your particular needs.
Then the second part is dictionary key, which is coming from Type objects being serialized.
I thought you can customize that by creating a custom JsonConverter, but it turns out that dictionary keys have "special" handling, meaning a more involved workaround. I don't have an example of the more involved workaround sorry.
I have an interface with exposes a property called Pages:
public interface INameSet
{
IQueryable<string> Names { get; }
}
I have this class which implements the interface and must also be parsed from a JSON object:
[DataContract(Name = "surveyPageSet")]
public class SurveyPage : INameSet
{
[DataMember(Name = "names")]
public List<string> SurveyNames { get; set; }
public IQueryable<string> Names
{
get
{
//Returns SurveyNames after some filtration logic
}
}
}
My problem is that when I pass in this object:
{
"names": ["testname"]
}
The JSON interpreter is trying to deserialize it to match the Names property instead of the SurveyNames property. I know this happens because when removing the implementation of the interface and changing SurveyNames to Names it populates the property fine. Is there any way to get it to serialize to the correct property or do I need to create a translator class that will generate the proper concretion of the INameSet interface?
EDIT: This is with the built-in serializer. If there is a solution with Newtonsoft/JSON.NET that would be fine with me.
JavaScriptSerializer doesn't allow for remapping of names out of the box, so don't use it.
Instead, use Json.NET or DataContractJsonSerializer. In fact, both should already work given the data contract attributes you have applied.
For instance, using Json.NET, if I do:
var page1 = JsonConvert.DeserializeObject<SurveyPage>(json);
Debug.Assert(page1.SurveyNames != null && page1.SurveyNames.SequenceEqual(new string [] { "testname" }));
Then there is no assert. Similarly there is no assert if I do:
var page2 = DataContractJsonSerializerHelper.GetObject<SurveyPage>(json);
Debug.Assert(page2.SurveyNames != null && page2.SurveyNames.SequenceEqual(new string[] { "testname" }));
using the helper class:
public static class DataContractJsonSerializerHelper
{
private static MemoryStream GenerateStreamFromString(string value)
{
return new MemoryStream(Encoding.Unicode.GetBytes(value ?? ""));
}
public static string GetJson<T>(T obj, DataContractJsonSerializer serializer)
{
using (var memory = new MemoryStream())
{
serializer.WriteObject(memory, obj);
memory.Seek(0, SeekOrigin.Begin);
using (var reader = new StreamReader(memory))
{
return reader.ReadToEnd();
}
}
}
public static string GetJson<T>(T obj) where T : class
{
DataContractJsonSerializer serializer = new DataContractJsonSerializer(typeof(T));
return GetJson(obj, serializer);
}
public static T GetObject<T>(string json) where T : class
{
DataContractJsonSerializer serializer = new DataContractJsonSerializer(typeof(T));
return GetObject<T>(json, serializer);
}
public static T GetObject<T>(string json, DataContractJsonSerializer serializer)
{
T obj = default(T);
using (var stream = GenerateStreamFromString(json))
{
obj = (T)serializer.ReadObject(stream);
}
return obj;
}
}
Update
If you really want to continue to use JavaScriptConverter, you can write your own JavaScriptConverter and deserialize each field manually. But it's a bother and I wouldn't recommend it.
I'm trying to deserialize a Facebook friend's Graph API call into a list of objects. The JSON object looks like:
{"data":[{"id":"518523721","name":"ftyft"},
{"id":"527032438","name":"ftyftyf"},
{"id":"527572047","name":"ftgft"},
{"id":"531141884","name":"ftftft"},
{"id":"532652067","name"...
List<EFacebook> facebooks = new JavaScriptSerializer().Deserialize<List<EFacebook>>(result);
It's not working, because the primitive object is invalid. How can I deserialize this?
You need to create a structure like this:
public class Friends
{
public List<FacebookFriend> data {get; set;}
}
public class FacebookFriend
{
public string id {get; set;}
public string name {get; set;}
}
Then you should be able to do:
Friends facebookFriends = new JavaScriptSerializer().Deserialize<Friends>(result);
The names of my classes are just an example. You should use proper names.
Adding a sample test:
string json =
#"{""data"":[{""id"":""518523721"",""name"":""ftyft""}, {""id"":""527032438"",""name"":""ftyftyf""}, {""id"":""527572047"",""name"":""ftgft""}, {""id"":""531141884"",""name"":""ftftft""}]}";
Friends facebookFriends = new System.Web.Script.Serialization.JavaScriptSerializer().Deserialize<Friends>(json);
foreach(var item in facebookFriends.data)
{
Console.WriteLine("id: {0}, name: {1}", item.id, item.name);
}
Produces:
id: 518523721, name: ftyft
id: 527032438, name: ftyftyf
id: 527572047, name: ftgft
id: 531141884, name: ftftft
Sometimes I prefer dynamic objects:
public JsonResult GetJson()
{
string res;
WebClient client = new WebClient();
// Download string
string value = client.DownloadString("https://api.instagram.com/v1/users/000000000/media/recent/?client_id=clientId");
// Write values
res = value;
dynamic dyn = JsonConvert.DeserializeObject(res);
var lstInstagramObjects = new List<InstagramModel>();
foreach(var obj in dyn.data)
{
lstInstagramObjects.Add(new InstagramModel()
{
Link = (obj.link != null) ? obj.link.ToString() : "",
VideoUrl = (obj.videos != null) ? obj.videos.standard_resolution.url.ToString() : "",
CommentsCount = int.Parse(obj.comments.count.ToString()),
LikesCount = int.Parse(obj.likes.count.ToString()),
CreatedTime = new System.DateTime(1970, 1, 1, 0, 0, 0, 0).AddSeconds((double.Parse(obj.created_time.ToString()))),
ImageUrl = (obj.images != null) ? obj.images.standard_resolution.url.ToString() : "",
User = new InstagramModel.UserAccount()
{
username = obj.user.username,
website = obj.user.website,
profile_picture = obj.user.profile_picture,
full_name = obj.user.full_name,
bio = obj.user.bio,
id = obj.user.id
}
});
}
return Json(lstInstagramObjects, JsonRequestBehavior.AllowGet);
}
A great way to automatically generate these classes for you is to copy your JSON output and throw it in here:
http://json2csharp.com/
It will provide you with a starting point to touch up your classes for deserialization.
Very easily we can parse JSON content with the help of dictionary and JavaScriptSerializer. Here is the sample code by which I parse JSON content from an ashx file.
var jss = new JavaScriptSerializer();
string json = new StreamReader(context.Request.InputStream).ReadToEnd();
Dictionary<string, string> sData = jss.Deserialize<Dictionary<string, string>>(json);
string _Name = sData["Name"].ToString();
string _Subject = sData["Subject"].ToString();
string _Email = sData["Email"].ToString();
string _Details = sData["Details"].ToString();
Newtonsoft.JSON is a good solution for these kind of situations. Also Newtonsof.JSON is faster than others, such as JavaScriptSerializer, DataContractJsonSerializer.
In this sample, you can the following:
var jsonData = JObject.Parse("your JSON data here");
Then you can cast jsonData to JArray, and you can use a for loop to get data at each iteration.
Also, I want to add something:
for (int i = 0; (JArray)jsonData["data"].Count; i++)
{
var data = jsonData[i - 1];
}
Working with dynamic object and using Newtonsoft serialize is a good choice.
I agree with Icarus (would have commented if I could),
but instead of using a CustomObject class,
I would use a Dictionary (in case Facebook adds something).
private class MyFacebookClass
{
public IList<IDictionary<string, string>> data { get; set; }
}
or
private class MyFacebookClass
{
public IList<IDictionary<string, object>> data { get; set; }
}
Serialization:
// Convert an object to JSON string format
string jsonData = JsonConvert.SerializeObject(obj);
Response.Write(jsonData);
Deserialization::
To deserialize a dynamic object
string json = #"{
'Name': 'name',
'Description': 'des'
}";
var res = JsonConvert.DeserializeObject< dynamic>(json);
Response.Write(res.Name);
If you're using .NET Core 3.0, you can use System.Text.Json (which is now built-in) to deserialize JSON.
The first step is to create classes to model the JSON. There are many tools which can help with this, and some of the answers here list them.
Some options are http://json2csharp.com, http://app.quicktype.io, or use Visual Studio (menu Edit → Paste Special → Paste JSON as classes).
public class Person
{
public string Id { get; set; }
public string Name { get; set; }
}
public class Response
{
public List<Person> Data { get; set; }
}
Then you can deserialize using:
var people = JsonSerializer.Deserialize<Response>(json);
If you need to add settings, such as camelCase handling, then pass serializer settings into the deserializer like this:
var options = new JsonSerializerOptions() { PropertyNamingPolicy = JsonNamingPolicy.CamelCase };
var person = JsonSerializer.Deserialize<Response>(json, options);
You can use this extensions
public static class JsonExtensions
{
public static T ToObject<T>(this string jsonText)
{
return JsonConvert.DeserializeObject<T>(jsonText);
}
public static string ToJson<T>(this T obj)
{
return JsonConvert.SerializeObject(obj);
}
}
Here is another site that will help you with all the code you need as long as you have a correctly formated JSON string available:
https://app.quicktype.io/