We Keep Coding

How Can I deserialize a json into a structure?

I have a class mapping like this:
public class Settings
{
[JsonProperty("id")]
public string Id { get; set; }
[JsonProperty("type")]
public string Type { get; set; }
[JsonProperty("content")]
public ContentStructure Content { get; set; }
}
public struct ContentStructure
{
public Content ContentClass;
public string ContentString;
public static implicit operator ContentStructure(Content content) => new ContentStructure { ContentClass = content };
public static implicit operator ContentStructure(string #string) => new ContentStructure { ContentString = #string };
}
public class Content
{
[JsonProperty("id")]
public string Id { get; set; }
[JsonProperty("duration")]
public long Duration { get; set; }
}
When I attempt to deserialize the following JSON string:
{
"id": "any_id",
"type": "any_type",
"content": {
"id": "any_id",
"duration": 1000
}
}
I always get the deserialized settings object with the property settings.Content.ContentClass null, but whenever my JSON string has the property "content" as string (instead of an object) the structure field ContentString comes correctly. What I am doing wrong? How can I can convert the JSON string above correctly?

Yet another solution could be to make use of the JsonSchema
First let's redefine your data model:
public abstract class Settings
{
[JsonProperty("id")]
public string Id { get; set; }
[JsonProperty("type")]
public string Type { get; set; }
}
public class SettingsV1 : Settings
{
[JsonProperty("content")]
public string Content { get; set; }
}
public class SettingsV2 : Settings
{
[JsonProperty("content")]
public Content Content { get; set; }
}
public class Content
{
[JsonProperty("id")]
public string Id { get; set; }
[JsonProperty("duration")]
public long Duration { get; set; }
}
Instead of having a middle man (ContentStructure) rather than you can have two separate Settings versions
The common fields are defined inside the abstract base class
Now, you can use these two versioned classes to define json schemas:
private static JSchema schemaV1;
private static JSchema schemaV2;
//...
var generator = new JSchemaGenerator();
schemaV1 = generator.Generate(typeof(SettingsV1));
schemaV2 = generator.Generate(typeof(SettingsV2));
Finally all you need to do is to do a preliminary check before calling the DeserializeObject with the proper type:
Settings settings = null;
var semiParsed = JObject.Parse(json);
if (semiParsed.IsValid(schemaV1))
{
settings = JsonConvert.DeserializeObject<SettingsV1>(json);
}
else if (semiParsed.IsValid(schemaV2))
{
settings = JsonConvert.DeserializeObject<SettingsV2>(json);
}
else
{
throw new NotSupportedException("The provided json format is not supported");
}

Use a Custom JsonConverter. Modify it based on your need.
[JsonConverter(typeof(ContentStructureConverter))]
public struct ContentStructure
{
public Content ContentClass;
public string ContentString;
public static implicit operator ContentStructure(Content content) => new ContentStructure { ContentClass = content };
public static implicit operator ContentStructure(string #string) => new ContentStructure { ContentString = #string };
}
public class ContentStructureConverter : JsonConverter
{
public override bool CanConvert(Type objectType)
{
return objectType == typeof(ContentStructure);
}
public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
{
ContentStructure contentStruct;
if (reader.ValueType == typeof(string))
contentStruct = reader.Value as string;
else
contentStruct = serializer.Deserialize<Content>(reader);
return contentStruct;
}
public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
{
ContentStructure? contentStruct = value as ContentStructure?;
if (contentStruct.HasValue && contentStruct.Value.ContentClass != null)
serializer.Serialize(writer, contentStruct.Value.ContentClass);
else
serializer.Serialize(writer, contentStruct.Value.ContentString);
}
}

The input json is wrong for your format.
If you use this json instead,
{
"id": "any_id",
"type": "any_type",
"content": {
"ContentClass" : {
"id": "any_id",
"duration": 1000
}
}
}
This way, it will work.
settings.Content.ContentClass is three layer but your is json two layer (settings.Content). So after "content", it is looking for id and duration which ContentStructure does not have these two fields.
My reasoning is when it encounters a value type (like {"field" : "value}), it will look for value type, like string, int or double. When it encounters a json type (like {"field" : {another json here} }), it will look for class or struct.

Deserialize property to different class based on other property c#

I know there are many similar questions on SO, however all the ones I've found require a shared base class in order to work.
With a stream of JSON data like this:
[
{
"webhookType": "order",
"data": {
"id": "eeiefj393",
"orderProperty": "Value"
}
},
{
"webhookType": "customer",
"data": {
"id": 29238,
"customerProperty": "Value"
}
}
]
I wish to deserialize this into two containers, List<Customer> and List<Order>. Where the two classes are as follows:
class Order
{
public string Id { get; set; }
public string OrderProperty { get; set; }
[...]
}
class Customer
{
public long Id { get; set; }
public string CustomerProperty { get; set; }
[...]
}
There may be shared property names however there are no shared properties + type between these two classes and so the solutions involing a sub class aren't working for me.

You need to create a JsonConverter.
DataConverter
public class WebHookConverter : JsonConverter
{
public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
{
throw new NotImplementedException();
}
public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
{
if (reader.TokenType == JsonToken.StartObject)
{
JObject item = JObject.Load(reader);
if (item["webhookType"].Value<string>() == "order")
{
var webhook = new WebHook
{
Type = item["webhookType"].Value<string>(),
Data = item["data"].ToObject<Order>()
};
return webhook;
}
else if (item["webhookType"].Value<string>() == "customer")
{
var webhook = new WebHook
{
Type = item["webhookType"].Value<string>(),
Data = item["data"].ToObject<Customer>()
};
return webhook;
}
}
return null;
}
public override bool CanConvert(Type objectType)
{
throw new NotImplementedException();
}
}
Objects
[JsonConverter(typeof(WebHookConverter))]
public class WebHook
{
[JsonProperty("webhookType")]
public string Type { get; set; }
public object Data { get; set; }
}
public class Order
{
public string Id { get; set; }
[JsonProperty("orderProperty")]
public string Property { get; set; }
}
public class Customer
{
public long Id { get; set; }
[JsonProperty("customerProperty")]
public string Property { get; set; }
}
Serialization
var json = File.ReadAllText("json1.json");
var obj = JsonConvert.DeserializeObject<List<WebHook>>(json);
var orderList = obj.Where(o => o.Type == "order").Select(o => o.Data).ToList();
var customerList = obj.Where(o => o.Type == "customer").Select(o => o.Data).ToList();
Output:

Newtonsoft deserialize multiple JSON files with cross references

I have two JSON files (that I can't change the format for) in the following format:
Main file -
[
{
"Name":"XYZ",
"UnitReferenceId":1
},
{
"Name":"ABC",
"UnitReferenceId":2
}
]
The lookup/reference JSON file -
[
{
"UnitReferenceId":1,
"Units":[
{
"Unit":"mg",
"Scale":1
},
{
"Unit":"gm",
"Scale":1000
},
{
"Unit":"kg",
"Scale":1000000
}
]
},
{
"UnitReferenceId":2,
"Units":[
{
"Unit":"mm",
"Scale":1
},
{
"Unit":"m",
"Scale":1000
},
{
"Unit":"km",
"Scale":1000000
}
]
}
]
How would I go about deserializing that into C# classes using Newtonsoft JSON into something like:
public class Widget
{
public string Name {get; set;}
public UnitReference UnitReference { get; set; }
}
public class UnitReference
{
public long UnitReferenceId { get; set; }
public List<Unit> Units { get; set; }
}
public class Unit
{
[JsonProperty("Unit")]
public string UnitValue { get; set; }
public long Scale { get; set; }
}
Any help would be greatly appreciated!

You can do this by reading your two JSON files as follows:
First read the lookup/reference JSON file for UnitReference as a List<UnitReference>, then convert to a Dictionary<long, UnitReference> lookup table.
Next, read the main file using a custom JsonConverter for Widget that is passed the Dictionary<long, UnitReference> lookup table and can translate between UnitReferenceId and UnitReference during reading and writing.
Thus your classes would look like the following:
public class UnitReference
{
readonly long unitReferenceId;
public UnitReference(long unitReferenceId)
{
this.unitReferenceId = unitReferenceId;
}
public long UnitReferenceId { get { return unitReferenceId; } }
public List<Unit> Units { get; set; }
}
public class Unit
{
[JsonProperty("Unit")]
public string UnitValue { get; set; }
public long Scale { get; set; }
}
public class Widget
{
public string Name { get; set; }
public UnitReference UnitReference { get; set; }
}
(My only modification was to make UnitReferenceId be read-only so that it safely could be used as a dictionary key.)
Then, define the following converter:
public class WidgetConverter : CustomPropertyConverterBase<Widget>
{
readonly IDictionary<long, UnitReference> units;
public WidgetConverter(IDictionary<long, UnitReference> units)
{
this.units = units;
}
protected override void ReadCustomProperties(JObject obj, Widget value, JsonSerializer serializer)
{
var id = (long?)obj.GetValue("UnitReferenceId", StringComparison.OrdinalIgnoreCase);
if (id != null)
value.UnitReference = units[id.Value];
}
protected override bool ShouldSerialize(JsonProperty property, object value)
{
if (property.UnderlyingName == nameof(Widget.UnitReference))
return false;
return base.ShouldSerialize(property, value);
}
protected override void WriteCustomProperties(JsonWriter writer, Widget value, JsonSerializer serializer)
{
if (value.UnitReference != null)
{
writer.WritePropertyName("UnitReferenceId");
writer.WriteValue(value.UnitReference.UnitReferenceId);
}
}
}
public abstract class CustomPropertyConverterBase<T> : JsonConverter where T : class
{
public override bool CanConvert(Type objectType)
{
return typeof(T).IsAssignableFrom(objectType);
}
public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
{
if (reader.TokenType == JsonToken.Null)
return null;
var jObj = JObject.Load(reader);
var contract = (JsonObjectContract)serializer.ContractResolver.ResolveContract(objectType);
var value = existingValue as T ?? (T)contract.DefaultCreator();
ReadCustomProperties(jObj, value, serializer);
// Populate the remaining properties.
using (var subReader = jObj.CreateReader())
{
serializer.Populate(subReader, value);
}
return value;
}
protected abstract void ReadCustomProperties(JObject obj, T value, JsonSerializer serializer);
public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
{
var contract = (JsonObjectContract)serializer.ContractResolver.ResolveContract(value.GetType());
writer.WriteStartObject();
foreach (var property in contract.Properties.Where(p => ShouldSerialize(p, value)))
{
var propertyValue = property.ValueProvider.GetValue(value);
if (propertyValue == null && serializer.NullValueHandling == NullValueHandling.Ignore)
continue;
writer.WritePropertyName(property.PropertyName);
serializer.Serialize(writer, propertyValue);
}
WriteCustomProperties(writer, (T)value, serializer);
writer.WriteEndObject();
}
protected virtual bool ShouldSerialize(JsonProperty property, object value)
{
return property.Readable && !property.Ignored && (property.ShouldSerialize == null || property.ShouldSerialize(value));
}
protected abstract void WriteCustomProperties(JsonWriter writer, T value, JsonSerializer serializer);
}
And deserialize as follows:
var units = JsonConvert.DeserializeObject<List<UnitReference>>(unitsJsonString)
.ToDictionary(u => u.UnitReferenceId);
var settings = new JsonSerializerSettings
{
Converters = { new WidgetConverter(units) },
};
var widgets = JsonConvert.DeserializeObject<List<Widget>>(widgetsJsonString, settings);
Notes:
Here I am deserializing from JSON strings for demo purposes, but you can deserialize directly from your file(s) as shown in Deserialize JSON from a file.
The base class CustomPropertyConverterBase<T> for WidgetConverter automatically reads and writes all properties for the object being (de)serialized. WidgetConverter then overrides this behavior for the UnitReference property only, avoiding the necessity to manually serialize all the remaining properties of Widget.
Sample fiddle.

I use json2csharp for creating my classes quickly. If you have to implement it in code, see JSON C# Class Generator Project.

Parse dynamic JSON

I am using c# and json.net 9.0.1
I have the following json
{
"lineups": [
{
"55": {
"id": "55",
"game_id": "1",
"player_id": "55",
"jersey_number": "78"
},
"56": {
"id": "56",
"game_id": "1",
"player_id": "56",
"jersey_number": "77"
},
"57": {
"id": "57",
"game_id": "1",
"player_id": "57",
"jersey_number": "76"
}
}
]
}
All of the array items are of type Player. How can I parse the json so that each item "55", "56", "57" are stored in a list of Players, List?
The source json can't be modified as it is coming from a 3rd party.
UPDATE
Modified the json to be valid,

If you created two classes like this:
public class Lineup
{
public List<Dictionary<string,Player>> lineups;
}
public class Player
{
public string id {get; set; }
public string game_id { get; set;}
public string player_id {get;set;}
public string jersey_number {get;set;}
}
Then you should (after you've fixed your invalid JSON), be able to deserialize like this:
var l = Newtonsoft.Json.JsonConvert.DeserializeObject<Lineup>(source);
Example: https://dotnetfiddle.net/e7eUUZ
You can also use the various attributes in JSON.Net to customize the deserialization. For example, you might want to use the JsonPropertyAttribute to map the names in your JSON source to C# property names that match the standard.

Given these classes:
public class Lineup
{
public List<Player> Players { get; set; }
}
public class Player
{
public string id { get; set; }
public string game_id { get; set; }
public string player_id { get; set; }
public string jersey_number { get; set; }
}
public class Result
{
public List<Lineup> Lineups { get; set; }
}
You could implement a custom JsonConverter like this:
public class LineupConverter : JsonConverter
{
public override bool CanConvert(Type objectType)
{
return objectType == typeof(Lineup);
}
public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
{
if (reader.TokenType == JsonToken.Null)
return null;
if (reader.TokenType != JsonToken.StartObject)
throw new Exception("Expected an object");
var jObject = (JObject)JObject.ReadFrom(reader);
// I suspect the property name are the same as the id property
// of the contained objects. Discarding the information from serialization
var players = jObject.Properties()
.Select(p => p.Value.ToObject<Player>());
return new Lineup
{
Players = players.ToList()
};
}
public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
{
throw new NotImplementedException();
}
}
And then use:
var lineups = JsonConvert.DeserializeObject<Result>(json, new LineupConverter());
You could also annotate the Player properties with JsonProperty attributes and have them more C#-like.

Deserializing complex Json objects

I want to deserialize a complex and let's say not well constructed json. That code that I wrote doesn't deserialize the object, the MovieInfo property is null. You can find the example json in the code. I want to avoid using JObject.Parse and dynamic objects. What am I missing here?
using System.Collections.Generic;
using Newtonsoft.Json;
namespace ComplexJsonExample
{
class Program
{
static void Main(string[] args)
{
string jsonInText = #"
{
""movies"" : [
{
""Harry Potter"" : [
{ ""rating"": ""great""},
{ ""rating"": ""horrible""}
]
},
{
""Guardians of the galaxy"" : [
{ ""rating"": ""cool""},
{ ""rating"": ""awesome""}
]
}
]
}
";
var movieList = JsonConvert.DeserializeObject<MovieList>(jsonInText);
}
}
public class MovieList
{
[JsonProperty("movies")]
public IList<Movie> Movies { get; set; }
}
public class Movie
{
IDictionary<string, IList<MovieRating>> MovieInfo { get; set; }
}
public class MovieRating
{
[JsonProperty("rating")]
public string Rating { get; set; }
}
}

It's a bit ugly, but you can do it like this:
class MovieList
{
[JsonProperty("movies")]
public Movie[] Movies { get; set; }
}
class Movie : Dictionary<string, MovieRating[]>
{
}
class MovieRating
{
[JsonProperty("rating")]
public string Rating { get; set; }
}
It's weird that the movie is a dictionary with only one key (its title), but it matches the JSON structure. You can always map it to something more sensible after deserialization.

I consider this a bit of a hack, but it works, and deserializes your json string into the format you required:
class MovieConverter : JsonConverter
{
public override bool CanConvert(Type objectType)
{
return objectType == typeof(Movie);
}
public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
{
var movie = new Movie(){
MovieInfo = new Dictionary<string,IList<MovieRating>>()
};
while (reader.Read() && reader.Value != null)
{
var name = (string)reader.Value;
reader.Read();
var ratings = ((JArray)serializer.Deserialize(reader)).Values<string>("rating");
movie.MovieInfo.Add(name, ratings.Select(r => new MovieRating(){ Rating = r}).ToList());
}
return movie;
}
public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
{
throw new NotImplementedException();
}
}
I did have to make two changes to your original objects, first I made the accessor for MovieInfo public so I could access it, and second to add the JsonConverterAttribute:
[JsonConverter(typeof(MovieConverter))]
public class Movie
{
public IDictionary<string, IList<MovieRating>> MovieInfo { get; set; }
}