C# 如何在JSON.NET中实现自定义JsonConverter以反序列化基类对象列表？

我试图扩展这里给出的JSON.net示例

我有另一个子类派生自基类/接口

public class Person
{
    public string FirstName { get; set; }
    public string LastName { get; set; }
}

public class Employee : Person
{
    public string Department { get; set; }
    public string JobTitle { get; set; }
}

public class Artist : Person
{
    public string Skill { get; set; }
}

List<Person> people  = new List<Person>
{
    new Employee(),
    new Employee(),
    new Artist(),
};

---

我不想使用TypeNameHandling JsonSerializerSettings。我特别寻找定制JsonConverter实现来处理这个问题。关于这一点的文档和示例在网上非常稀少。我似乎无法在JsonConverter中正确实现重写的ReadJson（）方法。

使用标准的

CustomCreationConverter

，我正在努力工作如何生成正确的类型（

Person

或

Employee

），因为为了确定这一点，您需要分析JSON，并且没有内置的方法使用

Create

方法进行分析

我发现了一个关于类型转换的讨论线程，结果它提供了答案。这里有一个链接：

所需的是子类化

JsonConverter

，重写

ReadJson

方法，并创建一个新的抽象

Create

方法，该方法接受

JObject

JObject类提供了加载JSON对象和 提供对此对象中的数据的访问

被重写的

ReadJson

方法创建一个

JObject

并调用

Create

方法（由派生的转换器类实现），传入

JObject

实例

然后可以通过检查某些字段的存在来分析此

JObject

实例，以确定正确的类型

示例

string json = "[{
        \"Department\": \"Department1\",
        \"JobTitle\": \"JobTitle1\",
        \"FirstName\": \"FirstName1\",
        \"LastName\": \"LastName1\"
    },{
        \"Department\": \"Department2\",
        \"JobTitle\": \"JobTitle2\",
        \"FirstName\": \"FirstName2\",
        \"LastName\": \"LastName2\"
    },
        {\"Skill\": \"Painter\",
        \"FirstName\": \"FirstName3\",
        \"LastName\": \"LastName3\"
    }]";

List<Person> persons = 
    JsonConvert.DeserializeObject<List<Person>>(json, new PersonConverter());

...

public class PersonConverter : JsonCreationConverter<Person>
{
    protected override Person Create(Type objectType, JObject jObject)
    {
        if (FieldExists("Skill", jObject))
        {
            return new Artist();
        }
        else if (FieldExists("Department", jObject))
        {
            return new Employee();
        }
        else
        {
            return new Person();
        }
    }

    private bool FieldExists(string fieldName, JObject jObject)
    {
        return jObject[fieldName] != null;
    }
}

public abstract class JsonCreationConverter<T> : JsonConverter
{
    /// <summary>
    /// Create an instance of objectType, based properties in the JSON object
    /// </summary>
    /// <param name="objectType">type of object expected</param>
    /// <param name="jObject">
    /// contents of JSON object that will be deserialized
    /// </param>
    /// <returns></returns>
    protected abstract T Create(Type objectType, JObject jObject);

    public override bool CanConvert(Type objectType)
    {
        return typeof(T).IsAssignableFrom(objectType);
    }

    public override bool CanWrite
    {
        get { return false; }
    }

    public override object ReadJson(JsonReader reader, 
                                    Type objectType, 
                                     object existingValue, 
                                     JsonSerializer serializer)
    {
        // Load JObject from stream
        JObject jObject = JObject.Load(reader);

        // Create target object based on JObject
        T target = Create(objectType, jObject);

        // Populate the object properties
        serializer.Populate(jObject.CreateReader(), target);

        return target;
    }
}

stringjson=”[{
\“部门”：“部门1”，
\“JobTitle\：\“JobTitle1\”，
\“FirstName\：\“FirstName1\”，
\“LastName\”：\“LastName1”
},{
\“部门”：“部门2”，
\“JobTitle\：\“JobTitle2\”，
\“FirstName\：\“FirstName2\”，
\“LastName\”：\“LastName 2”
},
{\'Skill\'：\'Painter\'，
\“FirstName\：\“FirstName3\”，
\“LastName\”：\“LastName 3”
}]";
名单人员=
反序列化对象（json，newPersonConverter（））；
...
公共类PersonConverter:JsonCreationConverter
{
受保护的重写人员创建（类型objectType，JObject JObject）
{
如果（字段存在（“技能”，作业对象））
{
返回新的艺术家（）；
}
否则（字段存在（“部门”，作业对象））
{
返回新员工（）；
}
其他的
{
返回新人（）；
}
}
私有布尔字段存在（字符串字段名，JObject JObject）
{
返回jObject[fieldName]！=null；
}
}
公共抽象类JsonCreationConverter:JsonConverter
{
/// 
///在JSON对象中创建基于属性的objectType实例
/// 
///预期的对象类型
/// 
///将被反序列化的JSON对象的内容
/// 
/// 
受保护的抽象T Create（类型objectType，JObject-JObject）；
公共覆盖布尔CanConvert（类型objectType）
{
返回typeof（T）.IsAssignableFrom（objectType）；
}
公共覆盖布尔可写
{
获取{return false；}
}
公共重写对象ReadJson（JsonReader，
类型objectType，
对象现有值，
JsonSerializer（序列化程序）
{
//从流中加载作业对象
JObject=JObject.Load（读卡器）；
//基于JObject创建目标对象
T target=Create（objectType，jObject）；
//填充对象属性
填充（jObject.CreateReader（），目标）；
回报目标；
}
}

我想我也会分享一个基于此的解决方案，它使用反射与Knowntype属性一起工作，必须从任何基类中获取派生类，解决方案可以从递归中受益，以找到最佳匹配类，尽管我的情况下不需要它，匹配是由给定给转换器的类型完成的，如果它有KnownTypes，它将扫描所有这些类型，直到它匹配一个包含json字符串中所有属性的类型，将选择第一个匹配的类型

用法非常简单，如下所示：

 string json = "{ Name:\"Something\", LastName:\"Otherthing\" }";
 var ret  = JsonConvert.DeserializeObject<A>(json, new KnownTypeConverter());

转换器代码：

/// <summary>
    /// Use KnownType Attribute to match a divierd class based on the class given to the serilaizer
    /// Selected class will be the first class to match all properties in the json object.
    /// </summary>
    public  class KnownTypeConverter : JsonConverter
    {
        public override bool CanConvert(Type objectType)
        {
            return System.Attribute.GetCustomAttributes(objectType).Any(v => v is KnownTypeAttribute);
        }

        public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
        {
            // Load JObject from stream
            JObject jObject = JObject.Load(reader);

            // Create target object based on JObject
            System.Attribute[] attrs = System.Attribute.GetCustomAttributes(objectType);  // Reflection. 

                // Displaying output. 
            foreach (System.Attribute attr in attrs)
            {
                if (attr is KnownTypeAttribute)
                {
                    KnownTypeAttribute k = (KnownTypeAttribute) attr;
                    var props = k.Type.GetProperties();
                    bool found = true;
                    foreach (var f in jObject)
                    {
                        if (!props.Any(z => z.Name == f.Key))
                        {
                            found = false;
                            break;
                        }
                    }

                    if (found)
                    {
                        var target = Activator.CreateInstance(k.Type);
                        serializer.Populate(jObject.CreateReader(),target);
                        return target;
                    }
                }
            }
            throw new ObjectNotFoundException();


            // Populate the object properties

        }

        public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
        {
            throw new NotImplementedException();
        }
    }

/// <summary>
/// Use KnownType Attribute to match a divierd class based on the class given to the serilaizer
/// Selected class will be the first class to match all properties in the json object.
/// </summary>
public class KnownTypeConverter : JsonConverter {
    public override bool CanConvert( Type objectType ) {
        return System.Attribute.GetCustomAttributes( objectType ).Any( v => v is KnownTypeAttribute );
    }

    public override bool CanWrite {
        get { return false; }
    }

    public override object ReadJson( JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer ) {
        // Load JObject from stream
        JObject jObject = JObject.Load( reader );

        // Create target object based on JObject
        System.Attribute[ ] attrs = System.Attribute.GetCustomAttributes( objectType );  // Reflection. 

        // check known types for a match. 
        foreach( var attr in attrs.OfType<KnownTypeAttribute>( ) ) {
            object target = Activator.CreateInstance( attr.Type );

            JObject jTest;
            using( var writer = new StringWriter( ) ) {
                using( var jsonWriter = new JsonTextWriter( writer ) ) {
                    serializer.Serialize( jsonWriter, target );
                    string json = writer.ToString( );
                    jTest = JObject.Parse( json );
                }
            }

            var jO = this.GetKeys( jObject ).Select( k => k.Key ).ToList( );
            var jT = this.GetKeys( jTest ).Select( k => k.Key ).ToList( );

            if( jO.Count == jT.Count && jO.Intersect( jT ).Count( ) == jO.Count ) {
                serializer.Populate( jObject.CreateReader( ), target );
                return target;
            }
        }

        throw new SerializationException( string.Format( "Could not convert base class {0}", objectType ) );
    }

    public override void WriteJson( JsonWriter writer, object value, JsonSerializer serializer ) {
        throw new NotImplementedException( );
    }

    private IEnumerable<KeyValuePair<string, JToken>> GetKeys( JObject obj ) {
        var list = new List<KeyValuePair<string, JToken>>( );
        foreach( var t in obj ) {
            list.Add( t );
        }
        return list;
    }
}

//
///使用KnownType属性根据给定给Serializer的类匹配divierd类
///所选类将是第一个匹配json对象中所有属性的类。
/// 
公共类KnownTypeConverter:JsonConverter
{
公共覆盖布尔CanConvert（类型objectType）
{
返回System.Attribute.GetCustomAttributes（objectType）.Any（v=>v为KnownTypeAttribute）；
}
公共重写对象ReadJson（JsonReader阅读器，类型objectType，对象existingValue，JsonSerializer序列化程序）
{
//从流中加载作业对象
JObject=JObject.Load（读卡器）；
//基于JObject创建目标对象
System.Attribute[]attrs=System.Attribute.GetCustomAttributes（objectType）；//反射。
//显示输出。
foreach（attrs中的System.Attribute attr）
{
if（属性为KnownTypeAttribute）
{
KnownTypeAttribute k=（KnownTypeAttribute）属性；
var props=k.Type.GetProperties（）；
布尔发现=真；
foreach（jObject中的var f）
{
如果（！props.Any（z=>z.Name==f.Key））
{
发现=错误；
打破
}
}
如果（找到）
{
var target=Activator.CreateInstance（k.Type）；
ser
/// <summary>
    /// Use KnownType Attribute to match a divierd class based on the class given to the serilaizer
    /// Selected class will be the first class to match all properties in the json object.
    /// </summary>
    public  class KnownTypeConverter : JsonConverter
    {
        public override bool CanConvert(Type objectType)
        {
            return System.Attribute.GetCustomAttributes(objectType).Any(v => v is KnownTypeAttribute);
        }

        public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
        {
            // Load JObject from stream
            JObject jObject = JObject.Load(reader);

            // Create target object based on JObject
            System.Attribute[] attrs = System.Attribute.GetCustomAttributes(objectType);  // Reflection. 

                // Displaying output. 
            foreach (System.Attribute attr in attrs)
            {
                if (attr is KnownTypeAttribute)
                {
                    KnownTypeAttribute k = (KnownTypeAttribute) attr;
                    var props = k.Type.GetProperties();
                    bool found = true;
                    foreach (var f in jObject)
                    {
                        if (!props.Any(z => z.Name == f.Key))
                        {
                            found = false;
                            break;
                        }
                    }

                    if (found)
                    {
                        var target = Activator.CreateInstance(k.Type);
                        serializer.Populate(jObject.CreateReader(),target);
                        return target;
                    }
                }
            }
            throw new ObjectNotFoundException();


            // Populate the object properties

        }

        public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
        {
            throw new NotImplementedException();
        }
    }

/// <summary>Creates a new reader for the specified jObject by copying the settings
/// from an existing reader.</summary>
/// <param name="reader">The reader whose settings should be copied.</param>
/// <param name="jToken">The jToken to create a new reader for.</param>
/// <returns>The new disposable reader.</returns>
public static JsonReader CopyReaderForObject(JsonReader reader, JToken jToken)
{
    JsonReader jTokenReader = jToken.CreateReader();
    jTokenReader.Culture = reader.Culture;
    jTokenReader.DateFormatString = reader.DateFormatString;
    jTokenReader.DateParseHandling = reader.DateParseHandling;
    jTokenReader.DateTimeZoneHandling = reader.DateTimeZoneHandling;
    jTokenReader.FloatParseHandling = reader.FloatParseHandling;
    jTokenReader.MaxDepth = reader.MaxDepth;
    jTokenReader.SupportMultipleContent = reader.SupportMultipleContent;
    return jTokenReader;
}

public override object ReadJson(JsonReader reader,
                                Type objectType,
                                object existingValue,
                                JsonSerializer serializer)
{
    if (reader.TokenType == JsonToken.Null)
        return null;
    // Load JObject from stream
    JObject jObject = JObject.Load(reader);
    // Create target object based on JObject
    T target = Create(objectType, jObject);
    // Populate the object properties
    using (JsonReader jObjectReader = CopyReaderForObject(reader, jObject))
    {
        serializer.Populate(jObjectReader, target);
    }
    return target;
}

/// <summary>Base Generic JSON Converter that can help quickly define converters for specific types by automatically
/// generating the CanConvert, ReadJson, and WriteJson methods, requiring the implementer only to define a strongly typed Create method.</summary>
public abstract class JsonCreationConverter<T> : JsonConverter
{
    /// <summary>Create an instance of objectType, based properties in the JSON object</summary>
    /// <param name="objectType">type of object expected</param>
    /// <param name="jObject">contents of JSON object that will be deserialized</param>
    protected abstract T Create(Type objectType, JObject jObject);

    /// <summary>Determines if this converted is designed to deserialization to objects of the specified type.</summary>
    /// <param name="objectType">The target type for deserialization.</param>
    /// <returns>True if the type is supported.</returns>
    public override bool CanConvert(Type objectType)
    {
        // FrameWork 4.5
        // return typeof(T).GetTypeInfo().IsAssignableFrom(objectType.GetTypeInfo());
        // Otherwise
        return typeof(T).IsAssignableFrom(objectType);
    }

    /// <summary>Parses the json to the specified type.</summary>
    /// <param name="reader">Newtonsoft.Json.JsonReader</param>
    /// <param name="objectType">Target type.</param>
    /// <param name="existingValue">Ignored</param>
    /// <param name="serializer">Newtonsoft.Json.JsonSerializer to use.</param>
    /// <returns>Deserialized Object</returns>
    public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
    {
        if (reader.TokenType == JsonToken.Null)
            return null;

        // Load JObject from stream
        JObject jObject = JObject.Load(reader);

        // Create target object based on JObject
        T target = Create(objectType, jObject);

        //Create a new reader for this jObject, and set all properties to match the original reader.
        JsonReader jObjectReader = jObject.CreateReader();
        jObjectReader.Culture = reader.Culture;
        jObjectReader.DateParseHandling = reader.DateParseHandling;
        jObjectReader.DateTimeZoneHandling = reader.DateTimeZoneHandling;
        jObjectReader.FloatParseHandling = reader.FloatParseHandling;

        // Populate the object properties
        serializer.Populate(jObjectReader, target);

        return target;
    }

    /// <summary>Serializes to the specified type</summary>
    /// <param name="writer">Newtonsoft.Json.JsonWriter</param>
    /// <param name="value">Object to serialize.</param>
    /// <param name="serializer">Newtonsoft.Json.JsonSerializer to use.</param>
    public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
    {
        serializer.Serialize(writer, value);
    }
}

public abstract class JsonCreationConverter<T> : JsonConverter
{
    protected abstract T Create(Type objectType, JObject jObject);

    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;

        // Load JObject from stream
        JObject jObject = JObject.Load(reader);

        // Create target object based on JObject
        T target = Create(objectType, jObject);

        // Populate the object properties
        StringWriter writer = new StringWriter();
        serializer.Serialize(writer, jObject);
        using (JsonTextReader newReader = new JsonTextReader(new StringReader(writer.ToString())))
        { 
            newReader.Culture = reader.Culture;
            newReader.DateParseHandling = reader.DateParseHandling;
            newReader.DateTimeZoneHandling = reader.DateTimeZoneHandling;
            newReader.FloatParseHandling = reader.FloatParseHandling;
            serializer.Populate(newReader, target);
        }

        return target;
    }

    public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
    {
        serializer.Serialize(writer, value);
    }
}

[KnownType(typeof(B))]
public class A
{
   public string Name { get; set; }
}

public class B : A
{
   public string LastName { get; set; }
}

/// <summary>
/// Use KnownType Attribute to match a divierd class based on the class given to the serilaizer
/// Selected class will be the first class to match all properties in the json object.
/// </summary>
public class KnownTypeConverter : JsonConverter {
    public override bool CanConvert( Type objectType ) {
        return System.Attribute.GetCustomAttributes( objectType ).Any( v => v is KnownTypeAttribute );
    }

    public override bool CanWrite {
        get { return false; }
    }

    public override object ReadJson( JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer ) {
        // Load JObject from stream
        JObject jObject = JObject.Load( reader );

        // Create target object based on JObject
        System.Attribute[ ] attrs = System.Attribute.GetCustomAttributes( objectType );  // Reflection. 

        // check known types for a match. 
        foreach( var attr in attrs.OfType<KnownTypeAttribute>( ) ) {
            object target = Activator.CreateInstance( attr.Type );

            JObject jTest;
            using( var writer = new StringWriter( ) ) {
                using( var jsonWriter = new JsonTextWriter( writer ) ) {
                    serializer.Serialize( jsonWriter, target );
                    string json = writer.ToString( );
                    jTest = JObject.Parse( json );
                }
            }

            var jO = this.GetKeys( jObject ).Select( k => k.Key ).ToList( );
            var jT = this.GetKeys( jTest ).Select( k => k.Key ).ToList( );

            if( jO.Count == jT.Count && jO.Intersect( jT ).Count( ) == jO.Count ) {
                serializer.Populate( jObject.CreateReader( ), target );
                return target;
            }
        }

        throw new SerializationException( string.Format( "Could not convert base class {0}", objectType ) );
    }

    public override void WriteJson( JsonWriter writer, object value, JsonSerializer serializer ) {
        throw new NotImplementedException( );
    }

    private IEnumerable<KeyValuePair<string, JToken>> GetKeys( JObject obj ) {
        var list = new List<KeyValuePair<string, JToken>>( );
        foreach( var t in obj ) {
            list.Add( t );
        }
        return list;
    }
}

 public class JsonKnownTypeConverter : JsonConverter
{
    public IEnumerable<Type> KnownTypes { get; set; }

    public JsonKnownTypeConverter() : this(ReflectTypes())
    {

    }
    public JsonKnownTypeConverter(IEnumerable<Type> knownTypes)
    {
        KnownTypes = knownTypes;
    }

    protected object Create(Type objectType, JObject jObject)
    {
        if (jObject["$type"] != null)
        {
            string typeName = jObject["$type"].ToString();
            return Activator.CreateInstance(KnownTypes.First(x => typeName == x.Name));
        }
        else
        {
            return Activator.CreateInstance(objectType);
        }
        throw new InvalidOperationException("No supported type");
    }

    public override bool CanConvert(Type objectType)
    {
        if (KnownTypes == null)
            return false;

        return (objectType.IsInterface || objectType.IsAbstract) && KnownTypes.Any(objectType.IsAssignableFrom);
    }

    public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
    {
        // Load JObject from stream
        JObject jObject = JObject.Load(reader);

        // Create target object based on JObject
        var target = Create(objectType, jObject);
        // Populate the object properties
        serializer.Populate(jObject.CreateReader(), target);
        return target;
    }

    public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
    {
        throw new NotImplementedException();
    }

    //Static helpers
    static Assembly CallingAssembly = Assembly.GetCallingAssembly();

    static Type[] ReflectTypes()
    {
        List<Type> types = new List<Type>();
        var referencedAssemblies = Assembly.GetExecutingAssembly().GetReferencedAssemblies();
        foreach (var assemblyName in referencedAssemblies)
        {
            Assembly assembly = Assembly.Load(assemblyName);
            Type[] typesInReferencedAssembly = GetTypes(assembly);
            types.AddRange(typesInReferencedAssembly);
        }

        return types.ToArray();
    }

    static Type[] GetTypes(Assembly assembly, bool publicOnly = true)
    {
        Type[] allTypes = assembly.GetTypes();

        List<Type> types = new List<Type>();

        foreach (Type type in allTypes)
        {
            if (type.IsEnum == false &&
               type.IsInterface == false &&
               type.IsGenericTypeDefinition == false)
            {
                if (publicOnly == true && type.IsPublic == false)
                {
                    if (type.IsNested == false)
                    {
                        continue;
                    }
                    if (type.IsNestedPrivate == true)
                    {
                        continue;
                    }
                }
                types.Add(type);
            }
        }
        return types.ToArray();
    }

GlobalConfiguration.Configuration.Formatters.JsonFormatter.SerializerSettings.Converters.Add(new JsonKnownTypeConverter());

    [JsonConverter(typeof(JsonSubtypes))]
    [JsonSubtypes.KnownSubTypeWithProperty(typeof(Employee), "JobTitle")]
    [JsonSubtypes.KnownSubTypeWithProperty(typeof(Artist), "Skill")]
    public class Person
    {
        public string FirstName { get; set; }
        public string LastName { get; set; }
    }

    public class Employee : Person
    {
        public string Department { get; set; }
        public string JobTitle { get; set; }
    }

    public class Artist : Person
    {
        public string Skill { get; set; }
    }

    [TestMethod]
    public void Demo()
    {
        string json = "[{\"Department\":\"Department1\",\"JobTitle\":\"JobTitle1\",\"FirstName\":\"FirstName1\",\"LastName\":\"LastName1\"}," +
                      "{\"Department\":\"Department1\",\"JobTitle\":\"JobTitle1\",\"FirstName\":\"FirstName1\",\"LastName\":\"LastName1\"}," +
                      "{\"Skill\":\"Painter\",\"FirstName\":\"FirstName1\",\"LastName\":\"LastName1\"}]";


        var persons = JsonConvert.DeserializeObject<IReadOnlyCollection<Person>>(json);
        Assert.AreEqual("Painter", (persons.Last() as Artist)?.Skill);
    }

    public class InterfaceConverter : JsonConverter
    {
    public override bool CanWrite => false;
    public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
    {
    }

    public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
    {
        var token = JToken.ReadFrom(reader);
        var typeVariable = this.GetTypeVariable(token);
        if (TypeExtensions.TryParse(typeVariable, out var implimentation))
        { }
        else if (!typeof(IEnumerable).IsAssignableFrom(objectType))
        {
            implimentation = this.GetImplimentedType(objectType);
        }
        else
        {
            var genericArgumentTypes = objectType.GetGenericArguments();
            var innerType = genericArgumentTypes.FirstOrDefault();
            if (innerType == null)
            {
                implimentation = typeof(IEnumerable);
            }
            else
            {
                Type genericType = null;
                if (token.HasAny())
                {
                    var firstItem = token[0];
                    var genericTypeVariable = this.GetTypeVariable(firstItem);
                    TypeExtensions.TryParse(genericTypeVariable, out genericType);
                }

                genericType = genericType ?? this.GetImplimentedType(innerType);
                implimentation = typeof(IEnumerable<>);
                implimentation = implimentation.MakeGenericType(genericType);
            }
        }

        return JsonConvert.DeserializeObject(token.ToString(), implimentation);
    }

    public override bool CanConvert(Type objectType)
    {
        return !typeof(IEnumerable).IsAssignableFrom(objectType) && objectType.IsInterface || typeof(IEnumerable).IsAssignableFrom(objectType) && objectType.GetGenericArguments().Any(t => t.IsInterface);
    }

    protected Type GetImplimentedType(Type interfaceType)
    {
        if (!interfaceType.IsInterface)
        {
            return interfaceType;
        }

        var implimentationQualifiedName = interfaceType.AssemblyQualifiedName?.Replace(interfaceType.Name, interfaceType.Name.Substring(1));
        return implimentationQualifiedName == null ? interfaceType : Type.GetType(implimentationQualifiedName) ?? interfaceType;
    }

    protected string GetTypeVariable(JToken token)
    {
        if (!token.HasAny())
        {
            return null;
        }

        return token.Type != JTokenType.Object ? null : token.Value<string>("$type");
    }
}

public static JsonSerializerSettings StandardSerializerSettings => new JsonSerializerSettings
    {
        Converters = new List<JsonConverter>
        {
            new InterfaceConverter()
        }
    };

{
    "documents": [
        {
            "document_id": "76b7be75-f4dc-44cd-90d2-0d1959922852",
            "date": "2019-12-10 11:32:49",
            "processed_date": "2019-12-10 11:32:49",
            "sender_id": "9dedee17-e43a-47f1-910e-3a88ff6bc258",
        },
        {
            "document_id": "5044a9ac-0314-4e9a-9e0c-817531120753",
            "date": "2019-12-10 11:32:44",
            "processed_date": "2019-12-10 11:32:44",
        }
    ], 
    "total": 2
}

/// <summary>
/// Service response model
/// </summary>
public class DocumentsRequestIdResponse
{
    [JsonProperty("documents")]
    public Document[] Documents { get; set; }

    [JsonProperty("total")]
    public int Total { get; set; }
}

// <summary>
/// Base document
/// </summary>
[JsonConverter(typeof(KnownTypeConverter))]
[KnownType(typeof(OutgoingDocument))]
[KnownType(typeof(IncomingDocument))]
public class Document
{
    [JsonProperty("document_id")]
    public Guid DocumentId { get; set; }

    [JsonProperty("date")]
    public DateTime Date { get; set; }

    [JsonProperty("processed_date")]
    public DateTime ProcessedDate { get; set; } 
}

/// <summary>
/// Outgoing document
/// </summary>
public class OutgoingDocument : Document
{
    // this property is optional and may not be present in the service's json response
    [JsonProperty("device_id")]
    public string DeviceId { get; set; }

    // this property is optional and may not be present in the service's json response
    [JsonProperty("msg_id")]
    public string MsgId { get; set; }
}

/// <summary>
/// Incoming document
/// </summary>
public class IncomingDocument : Document
{
    // this property is mandatory and is always populated by the service
    [JsonProperty("sender_sys_id")]
    public Guid SenderSysId { get; set; }
}

public class KnownTypeConverter : JsonConverter
{
    public override bool CanConvert(Type objectType)
    {
        return System.Attribute.GetCustomAttributes(objectType).Any(v => v is KnownTypeAttribute);
    }

    public override bool CanWrite => false;

    public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
    {
        // load the object 
        JObject jObject = JObject.Load(reader);

        // take custom attributes on the type
        Attribute[] attrs = Attribute.GetCustomAttributes(objectType);

        Type mostSuitableType = null;
        int countOfMaxMatchingProperties = -1;

        // take the names of elements from json data
        HashSet<string> jObjectKeys = GetKeys(jObject);

        // take the properties of the parent class (in our case, from the Document class, which is specified in DocumentsRequestIdResponse)
        HashSet<string> objectTypeProps = objectType.GetProperties(BindingFlags.Instance | BindingFlags.Public)
            .Select(p => p.Name)
            .ToHashSet();

        // trying to find the right "KnownType"
        foreach (var attr in attrs.OfType<KnownTypeAttribute>())
        {
            Type knownType = attr.Type;
            if(!objectType.IsAssignableFrom(knownType))
                continue;

            // select properties of the inheritor, except properties from the parent class and properties with "ignore" attributes (in our case JsonIgnoreAttribute and XmlIgnoreAttribute)
            var notIgnoreProps = knownType.GetProperties(BindingFlags.Instance | BindingFlags.Public)
                .Where(p => !objectTypeProps.Contains(p.Name)
                            && p.CustomAttributes.All(a => a.AttributeType != typeof(JsonIgnoreAttribute) && a.AttributeType != typeof(System.Xml.Serialization.XmlIgnoreAttribute)));

            //  get serializable property names
            var jsonNameFields = notIgnoreProps.Select(prop =>
            {
                string jsonFieldName = null;
                CustomAttributeData jsonPropertyAttribute = prop.CustomAttributes.FirstOrDefault(a => a.AttributeType == typeof(JsonPropertyAttribute));
                if (jsonPropertyAttribute != null)
                {
                    // take the name of the json element from the attribute constructor
                    CustomAttributeTypedArgument argument = jsonPropertyAttribute.ConstructorArguments.FirstOrDefault();
                    if(argument != null && argument.ArgumentType == typeof(string) && !string.IsNullOrEmpty((string)argument.Value))
                        jsonFieldName = (string)argument.Value;
                }
                // otherwise, take the name of the property
                if (string.IsNullOrEmpty(jsonFieldName))
                {
                    jsonFieldName = prop.Name;
                }

                return jsonFieldName;
            });


            HashSet<string> jKnownTypeKeys = new HashSet<string>(jsonNameFields);

            // by intersecting the sets of names we determine the most suitable inheritor
            int count = jObjectKeys.Intersect(jKnownTypeKeys).Count();

            if (count == jKnownTypeKeys.Count)
            {
                mostSuitableType = knownType;
                break;
            }

            if (count > countOfMaxMatchingProperties)
            {
                countOfMaxMatchingProperties = count;
                mostSuitableType = knownType;
            }
        }

        if (mostSuitableType != null)
        {
            object target = Activator.CreateInstance(mostSuitableType);
            using (JsonReader jObjectReader = CopyReaderForObject(reader, jObject))
            {
                serializer.Populate(jObjectReader, target);
            }
            return target;
        }

        throw new SerializationException($"Could not serialize to KnownTypes and assign to base class {objectType} reference");
    }

    public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
    {
        throw new NotImplementedException();
    }

    private HashSet<string> GetKeys(JObject obj)
    {
        return new HashSet<string>(((IEnumerable<KeyValuePair<string, JToken>>) obj).Select(k => k.Key));
    }

    public static JsonReader CopyReaderForObject(JsonReader reader, JObject jObject)
    {
        JsonReader jObjectReader = jObject.CreateReader();
        jObjectReader.Culture = reader.Culture;
        jObjectReader.DateFormatString = reader.DateFormatString;
        jObjectReader.DateParseHandling = reader.DateParseHandling;
        jObjectReader.DateTimeZoneHandling = reader.DateTimeZoneHandling;
        jObjectReader.FloatParseHandling = reader.FloatParseHandling;
        jObjectReader.MaxDepth = reader.MaxDepth;
        jObjectReader.SupportMultipleContent = reader.SupportMultipleContent;
        return jObjectReader;
    }
}