I am new at automapper and it is a very good stuff easy to use, but now I have a problem with it. Trying to convert my derived class to base and it gives me
AutoMapper.AutoMapperMappingException
Missing type map configuration or unsupported mapping.
Mapping types: ClientEventDb -> EventId
Database.ClientEventDb -> EventId
Destination path: ClientEvent
Source value:
Event:Login
Automapper wants to convert ClientEventDb to EventId? I don't understand why. EventId is an enum...
Please help me I have run out of ideas.
Here is the code which I run:
ClientEventDb[] edbl;
using (var context = new DbEntities())
{
edbl=context.Events.Take(1000).ToArray();
}
Mapper.CreateMap<ClientEventDb, ClientEvent>();
Console.WriteLine("hello");
return edbl.Select(edb => Mapper.Map<ClientEvent>(edb)).ToArray();
Here are my classes
[Table("events", Schema = "public")]
public class ClientEventDb : ClientEvent
{
public ClientEventDb(string userName, EventId happening, object userObject = null)
: base(userName, happening, userObject)
{
}
public ClientEventDb()
{
}
}
[ProtoContract]
[Table("events", Schema = "public")]
public class ClientEvent : ClientEventBase
{
[ProtoMember(1)]
[Column("username")]
public string UserName { get; private set; }
[ProtoMember(2)]
[Column("time")]
public DateTime DateTime { get; private set; }
[ProtoMember(3)]
[Key]
[Column("id")]
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public string Id { get; private set; }
[ProtoMember(4)]
[Column("data")]
public byte[] UserObject { get; set; }
public ClientEvent(string userName,EventId happening, object userObject=null) : base(happening)
{
UserName = userName;
DateTime = DateTime.Now;
//UserObject = null;
if (userObject!=null) throw new NotImplementedException();
}
public ClientEvent()
{
}
protected ClientEvent Clone()
{
return (ClientEvent)MemberwiseClone();
}
}
[ProtoContract]
[ProtoInclude(10, typeof(ClientEvent))]
public class ClientEventBase
{
[Column("eventid")]
[ProtoMember(1)]
public int EventIdValue { get; set; } //must be public because of entity framework
[NotMapped]
public EventId EventId
{
get { return (EventId) EventIdValue; }
set { EventIdValue = (int) value; }
}
public ClientEventBase(EventId eventId)
{
EventId = eventId;
}
public ClientEventBase()
{
}
public override string ToString()
{
return String.Format("Event:{0}",EventId);
}
}
public enum EventId
{
Login = 1,
Logout,
ExitApplication,
}
UPDATE
bugfix: ClientEvent [Key] attribute moved to id property
Solution was this (thx to stuartd):
ClientEventDb[] edbl;
using (var context = new DbEntities())
{
edbl=context.Events.ToArray();
}
Mapper.CreateMap<ClientEventDb, ClientEvent>().ConstructUsing((ClientEventDb src) => new ClientEvent());
return edbl.Select(Mapper.Map<ClientEvent>).ToArray();
AutoMapper is confused as its made to map between similar properties in different classes, you are using it incorrectly - you just need to go from the derived class to the base which does not require AutoMapper. You could use this to do what you need....
ClientEventDb[] edbl;
using (var context = new DbEntities())
{
edbl=context.Events.Take(1000).ToArray();
}
return edbl.Cast<ClientEvent>().ToList();
I'd be looking at why you even feel you need a derived ClientEventDb though - understand we dont have the whole picture here but it seems to do nothing in addition to what the base class already does.
The issue is that ClientEvent has two constructors but you have not told AutoMapper which to use.
If you want it to use your constructor with parameters, change your mapping code to this and it will work:
Mapper.CreateMap<ClientEventDb, ClientEvent>()
.ConstructUsing(src => new ClientEvent(src.UserName, src.EventId));
Or to make AutoMapper use the default constructor:
Mapper.CreateMap<ClientEventDb, ClientEvent>()
.ConstructUsing((ClientEventDb src) => new ClientEvent());
I have a class with a few properties and some methods
public class Content
{
public int Id { get; set; }
public string Application { get; set; }
public string Property1 { get; set; }
public string Property2 { get; set; }
public override bool Equals(object obj) {...}
public override int GetHashCode() {...}
}
With this Fluent NHibernate mapping:
public class ContentMapping : ClassMap<Content>
{
public ContentMapping()
{
Table("vw_all_contents");
CompositeId()
.KeyProperty(x => x.Id, "id")
.KeyProperty(x => x.Application, "application");
Map(x => x.Property1, "property1");
Map(x => x.Property2, "property2");
}
}
Up to here everything works fine.
I now want to populate the same object but with a table a federated table that connects to another database.
So I have:
public class ContentOnProductionDatabase : Content { }
With a mapping:
public class ContenOnProductionDatabasetMapping : ClassMap<ContentOnProductionDatabase>
{
public ContentOnProductionDatabaseMapping()
{
Table("vw_federated_all_contents");
CompositeId()
.KeyProperty(x => x.Id, "id")
.KeyProperty(x => x.Application, "application");
Map(x => x.Property1, "property1");
Map(x => x.Property2, "property2");
}
}
And here is where NHibernate gets really confused and the queries return mixed results from both databases.
The problem goes away if my ContentOnProductionDatabase does not extend Content but instead is a duplicate class like this:
public class ContentOnProductionDatabaseMapping
{
public int Id { get; set; }
public string Application { get; set; }
public string Property1 { get; set; }
public string Property2 { get; set; }
public override bool Equals(object obj) {...}
public override int GetHashCode() {...}
}
So now everything is fine but I don't like the fact that there is so much code duplication and it seems to me there must be some sort of Mapping configuration out there to force NHibernate to ignore the inheritance and differentiate the two, especially since they map to different databases.
The repository framework is an inbuilt one handles the session and the queries.
public class ContentRepository : NHibernateRepositoryBase, IContentRepository
{
public ContentRepository(INHibernateContext context, ISettingsManager settingsManager): base(context){ }
public Content ReadContent(int id, string application)
{
using (ISessionContainer container = Context.GetSessionContainer())
{
return
container.AsQueryable<Content>()
.FirstOrDefault(c => c.Id == id && c.Application == application);
// All queries using <Content> return the correct results
}
}
public ContentOnProductionDataBase ReadFederatedContent(int id, string application)
{
using (ISessionContainer container = Context.GetSessionContainer())
{
return
container.AsQueryable<ContentOnProductionDataBase>()
.FirstOrDefault(c => c.Id == id && c.Application == application);
// All queries using <ContentOnProductionDataBase> return the combined results of <Content> and <ContentOnProductionDataBase>
}
}
}
Internally the container.AsQueryable works by invoking this:
public IQueryable<TEntity> AsQueryable<TEntity>() where TEntity : class
{
return LinqExtensionMethods.Query<TEntity>(this.Session);
}
Any ideas how to get rid of the code duplication?
To define the class mapping and the properties only once, you have to define a base class and define the mapping with UseUnionSubclassForInheritanceMapping which will allow you to use independent tables per entity which is derived from that base class.
You don't have to but you should declare your base class as abstract, because it will not have a database representation. So persisting the base class will fail! Meaning, you don't want anyone to use it as an entity, instead use your derived classes...
To do so, create one base, and 2 derived classes which should be stored in one table per class.
public abstract class ContentBase
{
public virtual int Id { get; set; }
public virtual string Application { get; set; }
public virtual string Property1 { get; set; }
public virtual string Property2 { get; set; }
public override bool Equals(object obj)
{
[..]
}
public override int GetHashCode()
{
[..]
}
}
public class Content : ContentBase
{
}
public class ContentOnProductionDatabaset : ContentBase
{
}
The mapping of the base class must call UseUnionSubclassForInheritanceMapping, otherwise nHibernate would combine the classes.
public class ContentBaseMapping : ClassMap<ContentBase>
{
public ContentBaseMapping()
{
UseUnionSubclassForInheritanceMapping();
CompositeId()
.KeyProperty(x => x.Id, "id")
.KeyProperty(x => x.Application, "application");
Map(x => x.Property1, "property1");
Map(x => x.Property2, "property2");
}
}
The subclass mappings just have to define that the base is abstract.
Here you can also define each table name the entity should use.
public class ContentMapping : SubclassMap<Content>
{
public ContentMapping()
{
Table("vw_all_contents");
Abstract();
}
}
public class ContentOnProductionDatabaseMapping : SubclassMap<ContentOnProductionDatabaset>
{
public ContentOnProductionDatabaseMapping()
{
Table("vw_federated_all_contents");
Abstract();
}
}
Suppose I have the following class hierarchy:
public abstract class Organization
{
/* properties related to all organizations */
}
public sealed class Company : Organization
{
/* properties related to companies */
}
public sealed class NonProfitOrganization : Organization
{
/* properties related to non profit organizations */
}
Is it possible to have json.net use property (say "type" or "discriminator") to determine which type the object when it deserializes the organization? For example, the following should deserialize an instance of Company.
{
"type": "company"
/* other properties related to companies */
}
And the following should deserialize an instance of NonProfitOrganization.
{
"type": "non-profit"
/* other properties related to non profit */
}
When I call the following:
Organization organization = JsonConvert.DeserializeObject<Organization>(payload);
where payload is the above JSON snippets. I had a look at setting the "TypeNameHandling" on properties or classes but it serializes the whole .NET type, which isn't "portable" between the client and server when the classes are defined in different namespaces and assemblies.
I'd rather define the type is a neutral manner which clients written in any language can use to determine the actual type of the object type being serialized.
In case you are still looking, here is an example: http://james.newtonking.com/archive/2011/11/19/json-net-4-0-release-4-bug-fixes.aspx
This will allow you to create a table based mapping:
public class TypeNameSerializationBinder : SerializationBinder
{
public TypeNameSerializationBinder(Dictionary<Type, string> typeNames = null)
{
if (typeNames != null)
{
foreach (var typeName in typeNames)
{
Map(typeName.Key, typeName.Value);
}
}
}
readonly Dictionary<Type, string> typeToName = new Dictionary<Type, string>();
readonly Dictionary<string, Type> nameToType = new Dictionary<string, Type>(StringComparer.OrdinalIgnoreCase);
public void Map(Type type, string name)
{
this.typeToName.Add(type, name);
this.nameToType.Add(name, type);
}
public override void BindToName(Type serializedType, out string assemblyName, out string typeName)
{
var name = typeToName.Get(serializedType);
if (name != null)
{
assemblyName = null;
typeName = name;
}
else
{
assemblyName = serializedType.Assembly.FullName;
typeName = serializedType.FullName;
}
}
public override Type BindToType(string assemblyName, string typeName)
{
if (assemblyName == null)
{
var type = this.nameToType.Get(typeName);
if (type != null)
{
return type;
}
}
return Type.GetType(string.Format("{0}, {1}", typeName, assemblyName), true);
}
}
The code has a slight defect in that if a type name mapping is attempted where the type is unique but the name is already used, the Map method will throw an exception after the type-to-name mapping is already added leaving the table in an inconsistent state.
To take eulerfx's answer further; I wanted to apply DisplayName attribute to a class and have that automatically become the type name used; to that end:
public class DisplayNameSerializationBinder : DefaultSerializationBinder
{
private Dictionary<string, Type> _nameToType;
private Dictionary<Type, string> _typeToName;
public DisplayNameSerializationBinder()
{
var customDisplayNameTypes =
this.GetType()
.Assembly
//concat with references if desired
.GetTypes()
.Where(x => x
.GetCustomAttributes(false)
.Any(y => y is DisplayNameAttribute));
_nameToType = customDisplayNameTypes.ToDictionary(
t => t.GetCustomAttributes(false).OfType<DisplayNameAttribute>().First().DisplayName,
t => t);
_typeToName = _nameToType.ToDictionary(
t => t.Value,
t => t.Key);
}
public override void BindToName(Type serializedType, out string assemblyName, out string typeName)
{
if (false == _typeToName.ContainsKey(serializedType))
{
base.BindToName(serializedType, out assemblyName, out typeName);
return;
}
var name = _typeToName[serializedType];
assemblyName = null;
typeName = name;
}
public override Type BindToType(string assemblyName, string typeName)
{
if (_nameToType.ContainsKey(typeName))
return _nameToType[typeName];
return base.BindToType(assemblyName, typeName);
}
}
and usage example:
public class Parameter
{
public string Name { get; set; }
};
[DisplayName("bool")]
public class BooleanParameter : Parameter
{
}
[DisplayName("string")]
public class StringParameter : Parameter
{
public int MinLength { get; set; }
public int MaxLength { get; set; }
}
[DisplayName("number")]
public class NumberParameter : Parameter
{
public double Min { get; set; }
public double Max { get; set; }
public string Unit { get; set; }
}
[DisplayName("enum")]
public class EnumParameter : Parameter
{
public string[] Values { get; set; }
}
internal class Program
{
private static void Main(string[] args)
{
var parameters = new Parameter[]
{
new BooleanParameter() {Name = "alive"},
new StringParameter() {Name = "name", MinLength = 0, MaxLength = 10},
new NumberParameter() {Name = "age", Min = 0, Max = 120},
new EnumParameter() {Name = "status", Values = new[] {"Single", "Married"}}
};
JsonConvert.DefaultSettings = () => new JsonSerializerSettings
{
Binder = new DisplayNameSerializationBinder(),
TypeNameHandling = TypeNameHandling.Auto,
NullValueHandling = NullValueHandling.Ignore,
DefaultValueHandling = DefaultValueHandling.Ignore,
Formatting = Formatting.Indented,
ContractResolver = new CamelCasePropertyNamesContractResolver()
};
var json = JsonConvert.SerializeObject(parameters);
var loadedParams = JsonConvert.DeserializeObject<Parameter[]>(json);
Console.WriteLine(JsonConvert.SerializeObject(loadedParams));
}
}
output:
[
{
"$type": "bool",
"name": "alive"
},
{
"$type": "string",
"maxLength": 10,
"name": "name"
},
{
"$type": "number",
"max": 120.0,
"name": "age"
},
{
"$type": "enum",
"values": [
"Single",
"Married"
],
"name": "status"
}
]
I've written purely declarative solution with ability to specify custom discriminator field, and provide scoped name handling per base class (as opposed to usecure global JsonSerializationSettings, especially on different Web-Api when we do not have ability to specify custom JsonSerializationSettings).
using System;
using Newtonsoft.Json;
using Newtonsoft.Json.Linq;
using System.Reflection;
using System.Linq;
using System.Collections.Generic;
// Discriminated Json Converter (JsonSubtypes) implementation for .NET
//
// MIT License
//
// Copyright (c) 2016 Anatoly Ressin
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the "Software"),
// to deal in the Software without restriction, including without limitation
// the rights to use, copy, modify, merge, publish, distribute, sublicense,
// and/or sell copies of the Software, and to permit persons to whom the
// Software is furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.
////////////////////// USAGE ////////////////////////////////////////////////////////////////////////////////
[JsonConverter(typeof(JsonSubtypes))] // Discriminated base class SHOULD NOT be abstract
public class ShapeBase {
[JsonTag, JsonProperty("#type")] // it SHOULD contain a property marked with [JsonTag]
public string Type {get;set;} // only one [JsonTag] annotation allowed per discriminated class
// it COULD contain other properties, however this is NOT RECOMMENDED
// Rationale: instances of this class will be created at deserialization
// only for tag sniffing, and then thrown away.
}
public abstract class Shape: ShapeBase { // If you want abstract parent - extend the root
public abstract double GetArea(); // with needed abstract stuff, then use this class everywhere (see DEMO below)
}
[JsonSubtype("circle")] // Every final class-case SHOULD be marked with [JsonSubtype(tagValue)]
public class Circle: Shape { // Two disctinct variant classes MUST have distinct tagValues
[JsonProperty("super-radius")] // You CAN use any Json-related annotation as well
public double Radius { get; set; }
public override double GetArea() {
return Radius * Radius * Math.PI;
}
}
[JsonSubtype("rectangle")]
public class Rectangle: Shape {
public double Height { get; set; }
public double Width { get; set; }
public override double GetArea() {
return Width * Height;
}
}
[JsonSubtype("group")]
public class Group: Shape {
[JsonProperty("shapes")]
public List<Shape> Items { get; set; }
public override double GetArea() {
return Items.Select(item => item.GetArea()).Sum();
}
}
// Every final class-case SHOULD be registered with JsonSubtypes.register(typeof(YourConcreteClass))
// either manually or with auto-register capability:
// You can auto-register all classes marked with [JsonSubtype(tag)] in given Assembly
// using JsonSubtypes.autoRegister(yourAssembly)
////////////////// DEMO /////////////////////////////////////////////////////////////////////////////////
public class Program
{
public static void Main()
{
JsonSubtypes.autoRegister(Assembly.GetExecutingAssembly());
Shape original = new Group() {
Items = new List<Shape> {
new Circle() { Radius = 5 },
new Rectangle() { Height = 10, Width = 20 }
}
};
string str = JsonConvert.SerializeObject(original);
Console.WriteLine(str);
var copy = JsonConvert.DeserializeObject(str,typeof(Shape)) as Shape;
// Note: we can deserialize object using any class from the hierarchy.
// Under the hood, anyway, it will be deserialized using the top-most
// base class annotated with [JsonConverter(typeof(JsonSubtypes))].
// Thus, only soft-casts ("as"-style) are safe here.
Console.WriteLine("original.area = {0}, copy.area = {1}", original.GetArea(), copy.GetArea());
}
}
//////////////////////// IMPLEMENTATION //////////////////////////////////////////////////////////////////
public class JsonSubtypeClashException: Exception {
public string TagValue { get; private set;}
public Type RootType { get; private set; }
public Type OldType { get; private set; }
public Type NewType { get; private set; }
public JsonSubtypeClashException(Type rootType, string tagValue, Type oldType, Type newType): base(
String.Format(
"JsonSubtype Clash for {0}[tag={1}]: oldType = {2}, newType = {3}",
rootType.FullName,
tagValue,
oldType.FullName,
newType.FullName
)
) {
TagValue = tagValue;
RootType = rootType;
OldType = oldType;
NewType = newType;
}
}
public class JsonSubtypeNoRootException: Exception {
public Type SubType { get; private set; }
public JsonSubtypeNoRootException(Type subType): base(
String.Format(
"{0} should be inherited from the class with the [JsonConverter(typeof(JsonSubtypes))] attribute",
subType.FullName
)
) {
SubType = subType;
}
}
public class JsonSubtypeNoTagException: Exception {
public Type SubType { get; private set; }
public JsonSubtypeNoTagException(Type subType): base(
String.Format(
#"{0} should have [JsonSubtype(""..."")] attribute",
subType.FullName
)
) {
SubType = subType;
}
}
public class JsonSubtypeNotRegisteredException: Exception {
public Type Root { get; private set; }
public string TagValue { get; private set; }
public JsonSubtypeNotRegisteredException(Type root, string tagValue): base(
String.Format(
#"Unknown tag={1} for class {0}",
root.FullName,
tagValue
)
) {
Root = root;
TagValue = tagValue;
}
}
[AttributeUsage(AttributeTargets.Class)]
public class JsonSubtypeAttribute: Attribute {
private string tagValue;
public JsonSubtypeAttribute(string tagValue) {
this.tagValue = tagValue;
}
public string TagValue {
get {
return tagValue;
}
}
}
public static class JsonSubtypesExtension {
public static bool TryGetAttribute<T>(this Type t, out T attribute) where T: Attribute {
attribute = t.GetCustomAttributes(typeof(T), false).Cast<T>().FirstOrDefault();
return attribute != null;
}
private static Dictionary<Type, PropertyInfo> tagProperties = new Dictionary<Type, PropertyInfo>();
public static bool TryGetTagProperty(this Type t, out PropertyInfo tagProperty) {
if (!tagProperties.TryGetValue(t, out tagProperty)) {
JsonConverterAttribute conv;
if (t.TryGetAttribute(out conv) && conv.ConverterType == typeof(JsonSubtypes)) {
var props = (from prop in t.GetProperties() where prop.GetCustomAttribute(typeof(JsonTagAttribute)) != null select prop).ToArray();
if (props.Length == 0) throw new Exception("No tag");
if (props.Length > 1) throw new Exception("Multiple tags");
tagProperty = props[0];
} else {
tagProperty = null;
}
tagProperties[t] = tagProperty;
}
return tagProperty != null;
}
public static bool TryGetTagValue(this Type t, out string tagValue) {
JsonSubtypeAttribute subtype;
if (t.TryGetAttribute(out subtype)) {
tagValue = subtype.TagValue;
return true;
} else {
tagValue = null;
return false;
}
}
public static bool TryGetJsonRoot(this Type t, out Type root, out PropertyInfo tagProperty) {
root = t;
do {
if (root.TryGetTagProperty(out tagProperty)) {
return true;
}
root = root.BaseType;
} while (t != null);
return false;
}
}
public class JsonTagAttribute: Attribute {
}
public class JsonTagInfo {
public PropertyInfo Property { get; set; }
public string Value { get; set; }
}
public class JsonRootInfo {
public PropertyInfo Property { get; set; }
public Type Root { get; set; }
}
public abstract class DefaultJsonConverter: JsonConverter {
[ThreadStatic]
private static bool silentWrite;
[ThreadStatic]
private static bool silentRead;
public sealed override bool CanWrite {
get {
var canWrite = !silentWrite;
silentWrite = false;
return canWrite;
}
}
public sealed override bool CanRead {
get {
var canRead = !silentRead;
silentRead = false;
return canRead;
}
}
protected void _WriteJson(JsonWriter writer, Object value, JsonSerializer serializer) {
silentWrite = true;
serializer.Serialize(writer, value);
}
protected Object _ReadJson(JsonReader reader, Type objectType, Object existingValue, JsonSerializer serializer) {
silentRead = true;
return serializer.Deserialize(reader, objectType);
}
}
public class JsonSubtypes: DefaultJsonConverter {
private static Dictionary<Type, Dictionary<string, Type>> implementations = new Dictionary<Type, Dictionary<string, Type>>();
private static Dictionary<Type, JsonTagInfo> tags = new Dictionary<Type, JsonTagInfo>();
private static Dictionary<Type, JsonRootInfo> roots = new Dictionary<Type, JsonRootInfo>();
public static void register(Type newType) {
PropertyInfo tagProperty;
Type root;
if (newType.TryGetJsonRoot(out root, out tagProperty)) {
for(var t = newType; t != root; t = t.BaseType) {
roots[t] = new JsonRootInfo() {
Property = tagProperty,
Root = root
};
}
roots[root] = new JsonRootInfo() {
Property = tagProperty,
Root = root
};
Dictionary<string, Type> implementationMap;
if (!implementations.TryGetValue(root, out implementationMap)) {
implementationMap = new Dictionary<string, Type>();
implementations[root] = implementationMap;
}
JsonSubtypeAttribute attr;
if (!newType.TryGetAttribute(out attr)) {
throw new JsonSubtypeNoTagException(newType);
}
var tagValue = attr.TagValue;
Type oldType;
if (implementationMap.TryGetValue(tagValue, out oldType)) {
throw new JsonSubtypeClashException(root, tagValue, oldType, newType);
}
implementationMap[tagValue] = newType;
tags[newType] = new JsonTagInfo() {
Property = tagProperty,
Value = tagValue
};
} else {
throw new JsonSubtypeNoRootException(newType);
}
}
public static void autoRegister(Assembly assembly) {
foreach(var type in assembly.GetTypes().Where(type => type.GetCustomAttribute<JsonSubtypeAttribute>() != null)) {
register(type);
}
}
public override bool CanConvert(Type t) {
return true;
}
public static T EnsureTag<T>(T value) {
JsonTagInfo tagInfo;
if (tags.TryGetValue(value.GetType(), out tagInfo)) {
tagInfo.Property.SetValue(value, tagInfo.Value);
}
return value;
}
public override void WriteJson(JsonWriter writer, Object value, JsonSerializer serializer) {
_WriteJson(writer, EnsureTag(value), serializer);
}
public override Object ReadJson(JsonReader reader, Type objectType, Object existingValue, JsonSerializer serializer) {
JsonTagInfo tagInfo;
if (tags.TryGetValue(objectType, out tagInfo)) {
return _ReadJson(reader, objectType, existingValue, serializer);
} else {
JsonRootInfo rootInfo;
if (roots.TryGetValue(objectType, out rootInfo)) {
JToken t = JToken.ReadFrom(reader);
var stub = _ReadJson(t.CreateReader(), rootInfo.Root, existingValue, serializer);
var tagValue = rootInfo.Property.GetValue(stub) as string;
var implementationMap = implementations[rootInfo.Root];
Type implementation;
if (implementationMap.TryGetValue(tagValue, out implementation)) {
return ReadJson(t.CreateReader(), implementation, null, serializer);
} else {
throw new JsonSubtypeNotRegisteredException(rootInfo.Root, tagValue);
}
} else {
return _ReadJson(reader, objectType, existingValue, serializer);
}
}
}
public static T Deserialize<T>(string s) where T: class {
return JsonConvert.DeserializeObject(s, typeof(T)) as T;
}
public static string Serialize<T>(T value) where T: class {
return JsonConvert.SerializeObject(value);
}
}
output:
{"shapes":[{"super-radius":5.0,"#type":"circle"},{"Height":10.0,"Width":20.0,"#type":"rectangle"}],"#type":"group"}
original.area = 278.539816339745, copy.area = 278.539816339745
You can grab it here:
https://dotnetfiddle.net/ELcvnk
With another JsonSubtypes converter implementation.
Usage:
[JsonConverter(typeof(JsonSubtypes), "Sound")]
[JsonSubtypes.KnownSubType(typeof(Dog), "Bark")]
[JsonSubtypes.KnownSubType(typeof(Cat), "Meow")]
public class Animal
{
public virtual string Sound { get; }
public string Color { get; set; }
}
public class Dog : Animal
{
public override string Sound { get; } = "Bark";
public string Breed { get; set; }
}
public class Cat : Animal
{
public override string Sound { get; } = "Meow";
public bool Declawed { get; set; }
}
[TestMethod]
public void Demo()
{
var input = #"{""Sound"":""Bark"",""Breed"":""Jack Russell Terrier""}"
var animal = JsonConvert.DeserializeObject<Animal>(input);
Assert.AreEqual("Jack Russell Terrier", (animal as Dog)?.Breed);
}
the converter implementation can be directly downloaded from the repository: JsonSubtypes.cs and is also availble as a nuget package
Use this JsonKnownTypes, it's very similar way to use, add couple of attribute:
[JsonConverter(typeof(JsonKnownTypeConverter<Organization>))]
[JsonDiscriminator(Name = "discriminator")]
[JsonKnownType(typeof(Company), "company")]
[JsonKnownType(typeof(NonProfitOrganization), "non-profit")]
public abstract class Organization
{
/* properties related to all organizations */
}
public sealed class Company : Organization
{
/* properties related to companies */
}
public sealed class NonProfitOrganization : Organization
{
/* properties related to non profit organizations */
}
And serialize:
var json = JsonConvert.SerializeObject(youObject)
Output json:
{..., "discriminator":"non-profit"} //if object was NonProfitOrganization
Deserialization:
var organization = JsonConvert.DeserializeObject<Organization>(payload);