I am try to make conditional serialization base on rules that I give the moment I make the Serialization.
I know that I can use the ShouldSerialize+Name
[ProtoContract]
public class SomeType {
[ProtoMember(1)]
public string Name {get;set;}
private bool ShouldSerializeName() {
// return true to serialize Name, false otherwise
}
}
But what I need is like this example on Newtonsoft.Json.JsonConvert where I give the settings for what i am going to serialize the moment of serialization.
var oResolFilter = new ShouldSerializeContractResolver();
var settings = new JsonSerializerSettings { ContractResolver = oResolFilter };
var Results = JsonConvert.SerializeObject(this, settings);
and
class ShouldSerializeContractResolver : DefaultContractResolver
{
protected override JsonProperty CreateProperty(MemberInfo member, MemberSerialization memberSerialization)
{
JsonProperty property = base.CreateProperty(member, memberSerialization);
property.ShouldSerialize = true ; // ( or false)
return property;
}
}
So the question is - how can I do something similar as the JsonConvert on ProtoBuf-Net
reference
I look on most of answers, and on the examples and the source code on protobuf-net but fail to locate a similar solution... here are few questions that I look.
.net serialization: how to selectively ignore data fields
Conditional serialization with protobuf-net
Protobuf-net serialization of object (generic) throws error No serializer defined for type: System.Object
How to ignore default values while serializing json with Newtonsoft.Json
json.net example:
Newtonsoft JSON ShouldSerialize and inheritance
Related
We are running into a situation on an MVC3 project with both the Microsoft JSON serializers and JSON.NET.
Everybody knows DateTime's are basically broken in Microsoft's serializers, so we switched to JSON.NET to avoid this issue. That works great, except that some of the classes we are trying to serialize are POCOs with DataContract/DataMember attributes. They are defined in an assembly that is referenced in multiple places. Additionally, they have some other display properties that are not marked as DataMembers for efficiency. For instance, a Customer
[DataContract]
public class Customer
{
[DataMember]
public string FirstName { get; set;}
[DataMember]
public string LastName { get; set;}
public string FullName
{
get
{ return FirstName + " " + LastName; }
}
}
When this customer is passed over WCF the client side can reference that assembly and use the FullName just fine, but when serialized with JSON.NET it sees that FullName isn't a [DataMember] and doesn't serialize it. Is there an option to pass to JSON.NET to tell it to ignore the fact that a class has [DataContract] attribute applied?
Note:
Using the JavaScriptSerializer in .NET works fine for the FullName property, but DateTimes are broken. I need JSON.NET to ignore the fact that this class has DataContract/DataMember attributes and just do standard public field serialization like it would if they weren't there.
Simply use Json.Net's OptOut attribute. It will take precedence over DataContract.
[DataContract]
[JsonObject(MemberSerialization.OptOut)]
As Amry said you can uses your own IContractResolver.
Unfortunately the solution provided by Amry didn't work for me, below is the solution that I managed to get working:
public class AllPropertiesResolver : DefaultContractResolver
{
protected override JsonProperty CreateProperty(MemberInfo member, MemberSerialization memberSerialization)
{
JsonProperty property = base.CreateProperty(member, memberSerialization);
//property.HasMemberAttribute = true;
property.Ignored = false;
//property.ShouldSerialize = instance =>
//{
// return true;
//};
return property;
}
}
There are a few lines commented, these wern't required to make my solution work, but you never know!
This has the same usage as Amry's solution:
var json = JsonConvert.SerializeObject(result, new JsonSerializerSettings {
ContractResolver = new AllPropertiesResolver()
});
Hope this helps!
I was having a problem almost related to what you're having, and managed to find a solution by going through Json.NET's codes. So it may not be the best solution, but it works for me.
To do this, you need to implement your own IContractResolver. An over-simplified implementation of that to include all parameters and ignores all attributes (not just DataContract but other built-in Json.NET's rules as well, so whatever options you set that should originally affect the members selection is now being overidden by this code):
class AllPropertiesResolver : DefaultContractResolver
{
protected override List<MemberInfo> GetSerializableMembers(Type objectType)
{
return objectType.GetProperties()
.Where(p => p.GetIndexParameters().Length == 0)
.Cast<MemberInfo>()
.ToList();
}
}
And here comes the code usage example:
var json = JsonConvert.SerializeObject(result, new JsonSerializerSettings {
ContractResolver = new AllPropertiesResolver()
});
In accordance to the Json.NET documentation [DataMember] attributes are ignored if the properties are also annotated with Json.NET specific attributes (such as [JsonProperty]).See the Serialization Attributes documentation for details:
Json.NET attributes take presidence over standard .NET serialization attributes, e.g. if both JsonPropertyAttribute and DataMemberAttribute are present on a property and both customize the name, the name from JsonPropertyAttribute will be used.
The documentation only covers the name property, but for my experience the [JsonProperty] attribute also fully shadows settings done by the [DataMember] attribute. So, if it is feasible for your case, also add Json.NET attributes to the properties for which the [DataMember] annotation should be ignored.
If you want to ignore the presence of DataContractAttribute for all types without having to add additional attributes, then a custom contract resolver is the correct solution. However, as of Json.NET 9.0.1 Amry's resolver no longer works. Doolali's resolver works but it has the additional side effect of serializing all public properties including those marked with [JsonIgnore]. If you require a contract resolver that only ignores the presence of DataContractAttribute but otherwise behaves like the default contract resolver, the following can be used:
public class IgnoreDataContractContractResolver : DefaultContractResolver
{
static MemberSerialization RemoveDataContractAttributeMemberSerialization(Type type, MemberSerialization memberSerialization)
{
if (memberSerialization == MemberSerialization.OptIn)
{
type = Nullable.GetUnderlyingType(type) ?? type;
// Json.NET interprets DataContractAttribute as inherited despite the fact it is marked with Inherited = false
// https://json.codeplex.com/discussions/357850
// https://stackoverflow.com/questions/8555089/datacontract-and-inheritance
// https://github.com/JamesNK/Newtonsoft.Json/issues/603
// Thus we need to manually climb the type hierarchy to see if one is present.
var dataContractAttribute = type.BaseTypesAndSelf().Select(t => t.GetCustomAttribute<DataContractAttribute>()).FirstOrDefault(a => a != null);
var jsonObjectAttribute = type.GetCustomAttribute<JsonObjectAttribute>();
if (dataContractAttribute != null && jsonObjectAttribute == null)
memberSerialization = MemberSerialization.OptOut;
}
return memberSerialization;
}
protected override IList<JsonProperty> CreateProperties(Type type, MemberSerialization memberSerialization)
{
var properties = base.CreateProperties(type, RemoveDataContractAttributeMemberSerialization(type, memberSerialization));
return properties;
}
protected override JsonObjectContract CreateObjectContract(Type objectType)
{
var contract = base.CreateObjectContract(objectType);
contract.MemberSerialization = RemoveDataContractAttributeMemberSerialization(objectType, contract.MemberSerialization);
return contract;
}
}
public static class TypeExtensions
{
public static IEnumerable<Type> BaseTypesAndSelf(this Type type)
{
while (type != null)
{
yield return type;
type = type.BaseType;
}
}
}
You may want to cache the contract resolver for best performance.
Have you tried this?
IgnoreDataMemberAttribute
I have a class:
public class MyClass
{
public MyEnum Foo{ get; set; }
}
During serialization i'd like to change the output from
{
"Foo": 1
}
to
{
"Foo": "EnumName"
}
I've tried creating an IValueProvider but hit dead ends every way I go. (My scenario is a bit more complicated than stated; I need to find a way to do this entirely within the IContractResolver.)
You could create a custom ContractResolver inheriting from DefaultContractResolver that automatically applies StringEnumConverter to every contract for an enum or nullable enum:
public class StringEnumContractResolver : DefaultContractResolver
{
readonly StringEnumConverter converter;
public StringEnumContractResolver() : this(true, false) { }
public StringEnumContractResolver(bool allowIntegerValue, bool camelCaseText)
{
this.converter = new StringEnumConverter { AllowIntegerValues = allowIntegerValue, CamelCaseText = camelCaseText };
}
protected override JsonPrimitiveContract CreatePrimitiveContract(Type objectType)
{
var contract = base.CreatePrimitiveContract(objectType);
var type = Nullable.GetUnderlyingType(contract.UnderlyingType) ?? contract.UnderlyingType;
if (type.IsEnum && contract.Converter == null)
contract.Converter = converter;
return contract;
}
}
Notes:
If the enum type already has a JsonConverter applied, that is kept in preference to the default StringEnumConverter.
Adding the converter to the JsonPrimitiveContract for the enum itself, rather than to every JsonProperty for members that return the enum, ensures that the converter is applied to enums in collections and dictionaries.
The IValueProvider merely provides methods to get and set values and thus is less convenient to this purpose than the converter. You would need to perform a nested serialization and deserialization of the enum value as a JSON string inside it, but it isn't designed for this and so doesn't have access to the JSON reader, writer, or serializer. In addition, there is no value provider for dictionary values or collection items that are enums.
You may want to cache the contract resolver for best performance as explained here.
Sample .Net fiddle.
This question already has answers here:
Serialize Property, but Do Not Deserialize Property in Json.Net
(2 answers)
Closed 6 years ago.
I have a scenario with a class defined as below:
class MyObject
{
public DataDictionary MyObjectData { get; set; }
public bool ShouldSerializeMyObjectData() { return true; }
public bool ShouldDeserializeMyObjectData() { return false; }
}
When I attempt to serialize/deserialize that class with JSON.net, it takes the ShouldSerialize into account, but not the ShouldDeserialize.
According to the documentation, both should work the same way I guess. Is there something particular I should know? More generally, how should I deal with scenarios where I want to serialize a property but not deserialize it?
I'm using Json.NET 8.0 if that matters.
Thanks for your help.
The short answer to your question is, automatically checking for ShouldDeserialize{PropertyName}() is not currently implemented even though ShouldSerialize{PropertyName}() is. A longer answer and workaround follow.
The class JsonProperty is used internally by Json.NET to define a contract for how to map a JSON property to a .NET member or constructor parameter. It has two predicate properties, ShouldSerialize and ShouldDeserialize that, when non-null, prevent a property from being serialized and deserialized, respectively. Initializing each JsonProperty is the job of the ContractResolver. For each property {PropertyName}, Json.NET's default contract resolver automatically checks for the presence of a public bool ShouldSerialize{PropertyName}() method. If such a method exists, it adds a call to it in the ShouldSerialize predicate, thereby suppressing serialization when the method returns false. This was implemented because controlling property serialization via a method ShouldSerialize{PropertyName}() is a standard pattern supported by, e.g., XmlSerializer. For more background see the relevant Json.NET release notes.
For example, in the following class, serialization of MyObjectData will be suppressed unless MyObjectData.Count > 0:
class MyObject
{
public DataDictionary MyObjectData { get; set; }
public bool ShouldSerializeMyObjectData() { return MyObjectData != null && MyObjectData.Count > 0; }
}
JsonProperty.ShouldDeserialize, however, it is never set by the default contract resolver. This may be due to the fact that there is no standard pattern for deserialization equivalent to ShouldSerialize{PropertyName}() and so Newtonsoft never had any requests to implement such a pattern. Nevertheless, as you have noticed, infrastructure to support such a pattern exists, and so applications can create custom contract resolvers that do just that. In fact, Json.NET has an example of such a contract resolver in its own test suite:
public class ShouldDeserializeContractResolver : DefaultContractResolver
{
public static new readonly ShouldDeserializeContractResolver Instance = new ShouldDeserializeContractResolver();
protected override JsonProperty CreateProperty(MemberInfo member, MemberSerialization memberSerialization)
{
JsonProperty property = base.CreateProperty(member, memberSerialization);
MethodInfo shouldDeserializeMethodInfo = member.DeclaringType.GetMethod("ShouldDeserialize" + member.Name);
if (shouldDeserializeMethodInfo != null)
{
property.ShouldDeserialize = o => { return (bool)shouldDeserializeMethodInfo.Invoke(o, null); };
}
return property;
}
}
public class ShouldDeserializeTestClass
{
[JsonExtensionData]
public IDictionary<string, JToken> ExtensionData { get; set; }
public bool HasName { get; set; }
public string Name { get; set; }
public bool ShouldDeserializeName()
{
return HasName;
}
}
If you want to conditionally suppress deserialization of properties even when present in the JSON, you may use this contract resolver.
Notes:
If you do use a custom contract resolver, you should cache and reuse it for best performance.
JsonProperty.ShouldDeserialize is called before the property value is deserialized. If it returns true, the property is skipped, with no ability to examine the contents of the property. Thus it cannot be used to implement custom filtering based on that value.
A JSON object is defined by the JSON standard as an unordered set of name/value pairs. Thus a ShouldDeserialize method that assumes that other properties have already been read in may be brittle.
Instead, if you want to skip deserialization of one property based on the value of another, consider using an [OnDeserialized] callback and clearing the unwanted value there, after all properties have been deserialized.
Is there way to serialize private fields and autoproperties of an object?
The restriction is that I can't edit classes that i need to serialize which means:
1. I can't add any atributes on members (kinda datacontract)
2. I can't inherit it from an interface (kinda Ixmlserializable )
4. Add getter and setter properties for the fields
3. Class of the root object that i need to serialize is not even marked as serializable
Thanks
You may be able to do something like this (you'll have to get more creative if you have things like collections or non-serializable fields, but you get the idea):
var dict = new Dictionary<string, object>();
foreach (var field in typeof(Foo).GetFields(BindingFlags.Instance | BindingFlags.NonPublic))
{
dict[field.Name] = field.GetValue(f);
}
string json = JsonConvert.SerializeObject(dict);
Basically you're ripping the fields out one at a time, dumping them into a dictionary, then serializing the dictionary.
If you don't want to work with reflection yourself, you can read this article with a list of solutions for serialization.
You can override the DefaultContractResolver to do (de)serialization of only fields without having to decorate the classes:
public class FieldsOnlyContractResolver: DefaultContractResolver
{
protected override List<MemberInfo> GetSerializableMembers(Type objectType)
{
return objectType.GetFields(BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic)
.Cast<MemberInfo>().ToList();
}
protected override JsonProperty CreateProperty(MemberInfo member, MemberSerialization memberSerialization)
{
return base.CreateProperty(member, MemberSerialization.Fields);
}
}
Then, to use it, specify inside JsonConvert.(De)SerializeObject:
var jsonSettings = new JsonSerializerSettings() {
ContractResolver = new FieldsOnlyContractResolver()
};
var json = JsonConvert.SerializeObject(obj, jsonSettings);
var objAgain = JsonConvert.DeserializeObject<ObjType>(json, jsonSettings);
I have troubles deserializing my object. It contains following property:
public List<IShape> Shapes { get; set; };
and JSON.NET deserializer always tells me, that it is not possible to instantiate an interface.
I have several classes which implement interfaces which implement IShape interface, e.g. Polyline -> IPolyline -> IShape. I tried two solutions already:
https://stackoverflow.com/a/8031283/1525505
https://stackoverflow.com/a/12769061/1525505
But I got the same exception, that IShape cannot be instantied, was thrown.
I serialize the object with TypeNameHandling.Auto, TypeNameHandling.All doesn't help too, even when I use the converters mentioned in posts I linked above.
Does anyone know of a solution to this problem? If some code is needed I will gladly post it.
Here is a sample of JSON that is generated.
"$type": "SketchModel.Layer, SketchModel",
"Id": 57865477,
"Shapes": {
"$type": "System.Collections.Generic.List`1[[SketchModel.Shapes.AbstractShapes.IShape, SketchModel]], mscorlib",
"$values": [
{
"$type": "SketchModel.Shapes.Polyline, SketchModel",
This line is responsible for the problem:
"System.Collections.Generic.List`1[[SketchModel.Shapes.AbstractShapes.IShape, SketchModel]], mscorlib"
It simply doesn't know how to instantiate IShape. If I create a custom converter and let it return a Polyline for each IShape, it works, but doesn't create any other shapes (e.g. Ellipses).
In the
public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer) method which is overriden in the custom converter, if I let me print the full type name of objectType it's always IShape, never anything else...
The exception makes sense because the deserializer doesn't know what concrete type the interface is supposed to represent when hydrating.
During serialization, JSON.NET allows you to configure it to add some meta data to be used in this case. This SO question has an answer explaining how to configure it.
The configuration will add a type property to the JSON that will be used during deserialization.
I had exactly this problem and only solved it by explicitly providing a converter for the Type. It doesn't work if I use annotations - I need to pass the converters in at deserialization - basically like this:
state = JsonConvert.DeserializeObject<StateImpl>((String)stateObject, new JsonConverter[] { new StatePersistenceStateEntryConverter(), new StatePersistenceUserInteractionConverter() });
Where my StateImpl object included these properties:
[DataMember]
[JsonProperty("stateEntries", TypeNameHandling = TypeNameHandling.Auto)]
public List<IStateEntry> StateEntries
{
get;
set;
}
[DataMember]
[JsonProperty("precommitStateEntry", TypeNameHandling = TypeNameHandling.Auto)]
public IPrecommitStateEntry PrecommitStateEntry
{
get;
set;
}
IPrecommitStateEntry extends the IStateEntry interface (just FYI in case you're wondering why the extra logic in the converter).
Also - in my IStateEntry object, I have a similar child problem:
[DataMember]
[JsonProperty("userInteractions", TypeNameHandling = TypeNameHandling.Auto)]
public List<IUserInteraction> UserInteractions
{
get;
set;
}
So my object has child list properties of IStateEntry and an IStateEntry has a further child list of IUserInteraction. My converters are as follows:
public class StatePersistenceStateEntryConverter : CustomCreationConverter<IStateEntry>
{
public override IStateEntry Create(Type objectType)
{
if (objectType == typeof(IPrecommitStateEntry))
{
return new PrecommitStateEntry();
}
else
{
return new StateEntry();
}
}
}
And...
public class StatePersistenceUserInteractionConverter : CustomCreationConverter<IUserInteraction>
{
public override IUserInteraction Create(Type objectType)
{
return new UserInteraction();
}
}
Literally all they're doing is creating an instance of that particular object implementation.
So I don't know why the converters are needed as clearly a List can be instantiated - just not the IStateEntry individually. Clearly there's a bug in the NewtonSoft implementation somewhere - or I'm missing something fundamental.
Hope that helps. It was a frustrating few hours for me, but now working!
Without including concrete types within your Json string, you can use a JsonConverter to convert an IList<SomeInterface> to their concrete type:
Class to deserialize:
public partial class MovieInfo : IMovieInfo
{
~~~~
[JsonProperty("genres")]
[JsonConverter(typeof(ListConverter<IGenre, Genre>))]
public IList<IGenre> Genres { get; set; }
~~~~
}
JsonConverter example:
public class ListConverter<I, T> : JsonConverter
{
public override bool CanWrite => false;
public override bool CanRead => true;
public override bool CanConvert(Type objectType)
{
return objectType == typeof(I);
}
public override void WriteJson(JsonWriter writer,
object value, JsonSerializer serializer)
{
throw new InvalidOperationException("Use default serialization.");
}
public override object ReadJson(JsonReader reader,
Type objectType, object existingValue,
JsonSerializer serializer)
{
JArray jsonArray = JArray.Load(reader);
var deserialized = (List<T>)Activator.CreateInstance(typeof(List<T>));
serializer.Populate(jsonArray.CreateReader(), deserialized);
return deserialized as IList<I>;
}
}