I want to serialize an object with DataMember attribute to be ignored on some properties.
Say I have custom attribute MyIgnoreDataMember.
I want properties marked with it to be invisible for my custom DataContractSerializer, but visible for the normal DataContractSerializer.
And I have to use DataContractSerializer and nothing else.
The code is a Silverlight app.
Anyone have done subclassing DataContractSerializer successfully?
An answer to your question is complicated by the following issues:
DataContractSerializer is sealed, so can't be subclassed to check for an attribute like MyIgnoreDataMember.
Using a serialization surrogate to inject an appropriate DTO into your object graph during serialization would normally be the way to go -- but it looks like it's not available on silverlight, see this answer.
DataContractSerializer does not support the ShouldSerialize pattern, as explained here, so you can't just suppress serialization of the undesired properties via a callback method.
So, what are your options? Let's say your object graph looks like the following:
[DataContract(Name = "Root", Namespace = "http://www.MyNamespace.com")]
public class RootObject
{
[DataMember]
public NestedObject NestedObject { get; set; }
}
[DataContract(Name = "Nested", Namespace = "http://www.MyNamespace.com")]
public class NestedObject
{
[DataMember]
public string SensitiveData { get; set; }
[DataMember]
public string PublicData { get; set; }
}
And you want to conditionally suppress output of SensitiveData. Then the following are possibilities:
If you only need to eliminate a few properties, you could mark them with EmitDefaultValue = false and return a default value when some thread static is true, for instance:
[DataContract(Name = "Root", Namespace = "http://www.MyNamespace.com")]
public class RootObject
{
[DataMember]
public NestedObject NestedObject { get; set; }
}
[DataContract(Name = "Nested", Namespace = "http://www.MyNamespace.com")]
public class NestedObject
{
string sensitiveData;
[DataMember(IsRequired = false, EmitDefaultValue = false)]
public string SensitiveData
{
get
{
if (SerializationState.InCustomSerialization())
return null;
return sensitiveData;
}
set
{
sensitiveData = value;
}
}
[DataMember]
public string PublicData { get; set; }
}
public static class SerializationState
{
[ThreadStatic]
static bool inCustomSerialization;
public static bool InCustomSerialization()
{
return inCustomSerialization;
}
public static IDisposable SetInCustomDeserialization(bool value)
{
return new PushValue<bool>(value, () => inCustomSerialization, b => inCustomSerialization = b);
}
}
public struct PushValue<T> : IDisposable
{
Action<T> setValue;
T oldValue;
public PushValue(T value, Func<T> getValue, Action<T> setValue)
{
if (getValue == null || setValue == null)
throw new ArgumentNullException();
this.setValue = setValue;
this.oldValue = getValue();
setValue(value);
}
#region IDisposable Members
// By using a disposable struct we avoid the overhead of allocating and freeing an instance of a finalizable class.
public void Dispose()
{
if (setValue != null)
setValue(oldValue);
}
#endregion
}
And then, when serializing, do something like:
using (SerializationState.SetInCustomDeserialization(true))
{
// Serialize with data contract serializer.
}
Honestly quite ugly.
You could make an entire DTO hierarchy with the same contract names and namespaces as your real types, map the real classes to the DTO with something like automapper, and serialize the DTOs:
[DataContract(Name = "Root", Namespace = "http://www.MyNamespace.com")]
class RootObjectDTO
{
[DataMember]
public NestedObjectDTO NestedObject { get; set; }
}
[DataContract(Name = "Nested", Namespace = "http://www.MyNamespace.com")]
class NestedObjectDTO
{
[DataMember]
public string PublicData { get; set; }
}
If automapper is not available on silverlight, you can use DataContractSerializer itself to do the mapping, since the contract names and namespaces are identical. I.e. - serialize the real root object to an XML string (or to an XDocument as shown below), deserialize the intermediate XML to the DTO root, then serialize out the DTO.
You could serialize to an in-memory XDocument (which is available in silverlight) using the following extension class:
public static partial class DataContractSerializerHelper
{
public static XDocument SerializeContractToXDocument<T>(this T obj)
{
return obj.SerializeContractToXDocument(null);
}
public static XDocument SerializeContractToXDocument<T>(this T obj, DataContractSerializer serializer)
{
var doc = new XDocument();
using (var writer = doc.CreateWriter())
{
(serializer ?? new DataContractSerializer(obj.GetType())).WriteObject(writer, obj);
}
return doc;
}
public static T DeserializeContract<T>(this XDocument doc)
{
return doc.DeserializeContract<T>(null);
}
public static T DeserializeContract<T>(this XDocument doc, DataContractSerializer serializer)
{
if (doc == null)
throw new ArgumentNullException();
using (var reader = doc.CreateReader())
{
return (T)(serializer ?? new DataContractSerializer(typeof(T))).ReadObject(reader);
}
}
}
Next, prune the undesired elements using XPATH queries, and then serialize the XDocument to a final XML representation.
Finally, if performance and memory use are at a premium, you could use the ElementSkippingXmlTextWriter from this answer to prune undesired elements as they are written.
Related
We have some configuration files which were generated by serializing C# objects with Json.net.
We'd like to migrate one property of the serialised class away from being a simple enum property into a class property.
One easy way to do this, would be to leave the old enum property on the class, and arrange for Json.net to read this property when we load the config, but not to save it again when we next serialize the object. We'll deal with generating the new class from the old enum separately.
Is there any simple way to mark (e.g. with attributes) a property of a C# object, so that Json.net will ignore it ONLY when serializing, but attend to it when deserializing?
There are actually several fairly simple approaches you can use to achieve the result you want.
Let's assume, for example, that you have your classes currently defined like this:
class Config
{
public Fizz ObsoleteSetting { get; set; }
public Bang ReplacementSetting { get; set; }
}
enum Fizz { Alpha, Beta, Gamma }
class Bang
{
public string Value { get; set; }
}
And you want to do this:
string json = #"{ ""ObsoleteSetting"" : ""Gamma"" }";
// deserialize
Config config = JsonConvert.DeserializeObject<Config>(json);
// migrate
config.ReplacementSetting =
new Bang { Value = config.ObsoleteSetting.ToString() };
// serialize
json = JsonConvert.SerializeObject(config);
Console.WriteLine(json);
To get this:
{"ReplacementSetting":{"Value":"Gamma"}}
Approach 1: Add a ShouldSerialize method
Json.NET has the ability to conditionally serialize properties by looking for corresponding ShouldSerialize methods in the class.
To use this feature, add a boolean ShouldSerializeBlah() method to your class where Blah is replaced with the name of the property that you do not want to serialize. Make the implementation of this method always return false.
class Config
{
public Fizz ObsoleteSetting { get; set; }
public Bang ReplacementSetting { get; set; }
public bool ShouldSerializeObsoleteSetting()
{
return false;
}
}
Note: if you like this approach but you don't want to muddy up the public interface of your class by introducing a ShouldSerialize method, you can use an IContractResolver to do the same thing programmatically. See Conditional Property Serialization in the documentation.
Approach 2: Manipulate the JSON with JObjects
Instead of using JsonConvert.SerializeObject to do the serialization, load the config object into a JObject, then simply remove the unwanted property from the JSON before writing it out. It's just a couple of extra lines of code.
JObject jo = JObject.FromObject(config);
// remove the "ObsoleteSetting" JProperty from its parent
jo["ObsoleteSetting"].Parent.Remove();
json = jo.ToString();
Approach 3: Clever (ab)use of attributes
Apply a [JsonIgnore] attribute to the property that you do not want to be serialized.
Add an alternate, private property setter to the class with the same type as the original property. Make the implementation of that property set the original property.
Apply a [JsonProperty] attribute to the alternate setter, giving it the same JSON name as the original property.
Here is the revised Config class:
class Config
{
[JsonIgnore]
public Fizz ObsoleteSetting { get; set; }
[JsonProperty("ObsoleteSetting")]
private Fizz ObsoleteSettingAlternateSetter
{
// get is intentionally omitted here
set { ObsoleteSetting = value; }
}
public Bang ReplacementSetting { get; set; }
}
For any situation where it's acceptable to have your deserialization-only property be marked internal, there's a remarkably simple solution that doesn't depend on attributes at all. Simply mark the property as internal get, but public set:
public class JsonTest {
public string SomeProperty { internal get; set; }
}
This results in correct deserialization using default settings/resolvers/etc., but the property is stripped from serialized output.
I like sticking with attributes on this one, here is the method I use when needing to deserialize a property but not serialize it or vice versa.
STEP 1 - Create the custom attribute
public class JsonIgnoreSerializationAttribute : Attribute { }
STEP 2 - Create a custom Contract Reslover
class JsonPropertiesResolver : DefaultContractResolver
{
protected override List<MemberInfo> GetSerializableMembers(Type objectType)
{
//Return properties that do NOT have the JsonIgnoreSerializationAttribute
return objectType.GetProperties()
.Where(pi => !Attribute.IsDefined(pi, typeof(JsonIgnoreSerializationAttribute)))
.ToList<MemberInfo>();
}
}
STEP 3 - Add attribute where serialization is not needed but deserialization is
[JsonIgnoreSerialization]
public string Prop1 { get; set; } //Will be skipped when serialized
[JsonIgnoreSerialization]
public string Prop2 { get; set; } //Also will be skipped when serialized
public string Prop3 { get; set; } //Will not be skipped when serialized
STEP 4 - Use it
var sweet = JsonConvert.SerializeObject(myObj, new JsonSerializerSettings { ContractResolver = new JsonPropertiesResolver() });
Hope this helps! Also it's worth noting that this will also ignore the properties when Deserialization happens, when I am derserializing I just use the converter in the conventional way.
JsonConvert.DeserializeObject<MyType>(myString);
Use setter property:
[JsonProperty(nameof(IgnoreOnSerializing))]
public string IgnoreOnSerializingSetter { set { _ignoreOnSerializing = value; } }
[JsonIgnore]
private string _ignoreOnSerializing;
[JsonIgnore]
public string IgnoreOnSerializing
{
get { return this._ignoreOnSerializing; }
set { this._ignoreOnSerializing = value; }
}
Hope this help.
After i spent a quite long time searching how to flag a class property to be De-Serializable and NOT Serializable i found that there's no such thing to do that at all; so i came up with a solution that combines two different libraries or serialization techniques (System.Runtime.Serialization.Json & Newtonsoft.Json) and it worked for me like the following:
flag all your class and sub-classes as "DataContract".
flag all the properties of your class and sub-classes as "DataMember".
flag all the properties of your class and sub-classes as "JsonProperty" except those you want them not to be serialized.
now flag the properties the you do NOT want it to be serialized as "JsonIgnore".
then Serialize using "Newtonsoft.Json.JsonConvert.SerializeObject" and De-Serialize using "System.Runtime.Serialization.Json.DataContractJsonSerializer".
using System;
using System.Collections.Generic;
using Newtonsoft.Json;
using System.Runtime.Serialization;
using System.IO;
using System.Runtime.Serialization.Json;
using System.Text;
namespace LUM_Win.model
{
[DataContract]
public class User
{
public User() { }
public User(String JSONObject)
{
MemoryStream stream = new MemoryStream(Encoding.Unicode.GetBytes(JSONObject));
DataContractJsonSerializer dataContractJsonSerializer = new DataContractJsonSerializer(typeof(User));
User user = (User)dataContractJsonSerializer.ReadObject(stream);
this.ID = user.ID;
this.Country = user.Country;
this.FirstName = user.FirstName;
this.LastName = user.LastName;
this.Nickname = user.Nickname;
this.PhoneNumber = user.PhoneNumber;
this.DisplayPicture = user.DisplayPicture;
this.IsRegistred = user.IsRegistred;
this.IsConfirmed = user.IsConfirmed;
this.VerificationCode = user.VerificationCode;
this.Meetings = user.Meetings;
}
[DataMember(Name = "_id")]
[JsonProperty(PropertyName = "_id")]
public String ID { get; set; }
[DataMember(Name = "country")]
[JsonProperty(PropertyName = "country")]
public String Country { get; set; }
[DataMember(Name = "firstname")]
[JsonProperty(PropertyName = "firstname")]
public String FirstName { get; set; }
[DataMember(Name = "lastname")]
[JsonProperty(PropertyName = "lastname")]
public String LastName { get; set; }
[DataMember(Name = "nickname")]
[JsonProperty(PropertyName = "nickname")]
public String Nickname { get; set; }
[DataMember(Name = "number")]
[JsonProperty(PropertyName = "number")]
public String PhoneNumber { get; set; }
[DataMember(Name = "thumbnail")]
[JsonProperty(PropertyName = "thumbnail")]
public String DisplayPicture { get; set; }
[DataMember(Name = "registered")]
[JsonProperty(PropertyName = "registered")]
public bool IsRegistred { get; set; }
[DataMember(Name = "confirmed")]
[JsonProperty(PropertyName = "confirmed")]
public bool IsConfirmed { get; set; }
[JsonIgnore]
[DataMember(Name = "verification_code")]
public String VerificationCode { get; set; }
[JsonIgnore]
[DataMember(Name = "meeting_ids")]
public List<Meeting> Meetings { get; set; }
public String toJSONString()
{
return JsonConvert.SerializeObject(this, new JsonSerializerSettings() { NullValueHandling = NullValueHandling.Ignore });
}
}
}
Hope that helps ...
Depending on where in the application this takes place and if it's just one property, one manual way you can do this is by setting the property value to null and then on the model you can specify that the property be ignored if the value is null:
[JsonProperty(NullValueHandling = NullValue.Ignore)]
public string MyProperty { get; set; }
If you are working on an ASP.NET Core web app, you can globally set this for all properties in all models by setting this in your Startup.cs file:
public void ConfigureServices(IServiceCollection services) {
// other configuration here
services.AddMvc()
.AddJsonOptions(options => options.SerializerSettings.NullValueHandling = NullValueHandling.Ignore);
}
with reference to #ThoHo's solution, using the setter is actually all that is needed, with no additional tags.
For me I previously had a single reference Id, that I wanted to load and add to the new collection of reference Ids. By changing the definition of the reference Id to only contain a setter method, which added the value to the new collection. Json can't write the value back if the Property doesn't have a get; method.
// Old property that I want to read from Json, but never write again. No getter.
public Guid RefId { set { RefIds.Add(value); } }
// New property that will be in use from now on. Both setter and getter.
public ICollection<Guid> RefIds { get; set; }
This class is now backwards compatible with the previous version and only saves the RefIds for the new versions.
To build upon Tho Ho's answer, this can also be used for fields.
[JsonProperty(nameof(IgnoreOnSerializing))]
public string IgnoreOnSerializingSetter { set { IgnoreOnSerializing = value; } }
[JsonIgnore]
public string IgnoreOnSerializing;
If you use JsonConvert,IgnoreDataMemberAttribute is ok.My standard library not refrence Newton.Json,and I use [IgnoreDataMember] to control object serialize.
From Newton.net help document.
Is there any simple way to mark (e.g. with attributes) a property of a C# object, so that Json.net will ignore it ONLY when serializing, but attend to it when deserializing?
The easiest way I've found as of this writing is to include this logic in your IContractResolver.
Sample code from above link copied here for posterity:
public class Employee
{
public string Name { get; set; }
public Employee Manager { get; set; }
public bool ShouldSerializeManager()
{
// don't serialize the Manager property if an employee is their own manager
return (Manager != this);
}
}
public class ShouldSerializeContractResolver : DefaultContractResolver
{
public new static readonly ShouldSerializeContractResolver Instance = new ShouldSerializeContractResolver();
protected override JsonProperty CreateProperty(MemberInfo member, MemberSerialization memberSerialization)
{
JsonProperty property = base.CreateProperty(member, memberSerialization);
if (property.DeclaringType == typeof(Employee) && property.PropertyName == "Manager")
{
property.ShouldSerialize =
instance =>
{
Employee e = (Employee)instance;
return e.Manager != e;
};
}
return property;
}
}
All of the answers are good but this approach seemed like the cleanest way. I actually implemented this by looking for an attribute on the property for SkipSerialize and SkipDeserialize so you can just mark up any class you control. Great question!
Jraco11's answer is very neat. In case, if you want to use the same IContractResolver both for serialization and deserialization, then you can use the following:
public class JsonPropertiesResolver : DefaultContractResolver
{
protected override JsonProperty CreateProperty(MemberInfo member, MemberSerialization memberSerialization)
{
JsonProperty property = base.CreateProperty(member, memberSerialization);
if (member.IsDefined(typeof(JsonIgnoreSerializationAttribute)))
{
property.ShouldSerialize = instance => false;
}
return property;
}
}
thats will do the trick, create a property with set only
example 1:
https://dotnetfiddle.net/IxMXcG
[JsonProperty("disabled-protections")]
public JArray DisabledProtections { set => IsPartialResult = (value != null && value.HasValues); }
public bool IsPartialResult { get; private set; }
example 2:
private JArray _disabledProtections;
[JsonProperty("disabled-protections")]
public JArray DisabledProtections { set => _disabledProtections = value; }
public bool IsPartialResult => _disabledProtections != null && _disabledProtections.HasValues;
Use [JsonIgnore] attribute in the public property of the model class.
I am using MetadataType to define Json.NET attributes for the following type, then serializing it using Json.NET inside its ToString() method:
namespace ConsoleApp1
{
public interface ICell
{
int Id { get; }
}
public interface IEukaryote
{
System.Collections.Generic.IEnumerable<ICell> Cells { get; }
string GenericName { get; }
}
public sealed partial class PlantCell
: ICell
{
public int Id => 12324;
}
public sealed partial class Plant
: IEukaryote
{
private readonly System.Collections.Generic.IDictionary<string, object> _valuesDict;
public Plant()
{
_valuesDict = new System.Collections.Generic.Dictionary<string, object>();
var cells = new System.Collections.Generic.List<PlantCell>();
cells.Add(new PlantCell());
_valuesDict["Cells"] = cells;
_valuesDict["GenericName"] = "HousePlant";
}
public System.Collections.Generic.IEnumerable<ICell> Cells => _valuesDict["Cells"] as System.Collections.Generic.IEnumerable<ICell>;
public string GenericName => _valuesDict["GenericName"] as string;
public int SomethingIDoNotWantSerialized => 99999;
public override string ToString()
{
return Newtonsoft.Json.JsonConvert.SerializeObject(this,
new Newtonsoft.Json.JsonSerializerSettings()
{
ContractResolver = new Newtonsoft.Json.Serialization.CamelCasePropertyNamesContractResolver()
}
);
}
}
[System.ComponentModel.DataAnnotations.MetadataType(typeof(PlantMetadata))]
public sealed partial class Plant
{
[Newtonsoft.Json.JsonObject(Newtonsoft.Json.MemberSerialization.OptIn)]
internal sealed class PlantMetadata
{
[Newtonsoft.Json.JsonProperty]
public System.Collections.Generic.IEnumerable<ICell> Cells;
[Newtonsoft.Json.JsonProperty]
public string GenericName;
//...
}
}
class Program
{
static void Main(string[] args)
{
var plant = new Plant();
System.Console.WriteLine(System.String.Format("Output is {0}", plant.ToString()));
System.Console.ReadKey();
}
}
}
My problem is that Plant.ToString() will return '{}'. Why is that? It was working before. The only change I made was in PlantMetadata where I altered the MemberSerialization to OptIn instead of OptOut, as I had less properties I wanted included than left out.
As stated by Newtonsoft in this issue, MetadataTypeAttribute attributes are in fact supported by Json.NET. However, it appears that Json.NET requires that the MetadataClassType members must be properties when the corresponding "real" members are properties, and fields when the corresponding "real" members are fields. Thus, if I define your Plant type as follows, with two properties and one field to be serialized:
public sealed partial class Plant : IEukaryote
{
public System.Collections.Generic.IEnumerable<ICell> Cells { get { return (_valuesDict["Cells"] as System.Collections.IEnumerable).Cast<ICell>(); } }
public string GenericName { get { return _valuesDict["GenericName"] as string; } }
public string FieldIWantSerialized;
public int SomethingIDoNotWantSerialized { get { return 99999; } }
// Remainder as before.
Then the PlantMetadata must also have two properties and one field for them to be serialized successfully:
//Metadata.cs
[System.ComponentModel.DataAnnotations.MetadataType(typeof(PlantMetadata))]
public sealed partial class Plant
{
[JsonObject(MemberSerialization.OptIn)]
internal sealed class PlantMetadata
{
[JsonProperty]
public IEnumerable<ICell> Cells { get; set; }
[JsonProperty]
public string GenericName { get; set; }
[JsonProperty]
public string FieldIWantSerialized;
}
}
If I make Cells or GenericName be fields, or FieldIWantSerialized be a property, then they do not get opted into serialization.
Sample working .Net Fiddle.
Note that, in addition, I have found that the MetadataClassType properties apparently must have the same return type as the real properties. If I change your PlantMetadata as follows:
[JsonObject(MemberSerialization.OptIn)]
internal sealed class PlantMetadata
{
[JsonProperty]
public object Cells { get; set; }
[JsonProperty]
public object GenericName { get; set; }
[JsonProperty]
public object FieldIWantSerialized;
}
Then only FieldIWantSerialized is serialized, not the properties. .Net Fiddle #2 showing this behavior. This may be a Newtonsoft issue; as stated in the Microsoft documentation Defining Attributes in Metadata Classes:
The actual type of these properties is not important, and is ignored
by the compiler. The accepted approach is to declare them all as of
type Object.
If it matters, you could report an issue about the return type restriction to Newtonsoft - or report an issue asking that details of their support for MetadataTypeAttribute be more fully documented.
I have small problem - XML deserialization completely ignores items, which are out of alphabetic order. In example object (description in end of question), Birthday node is after FirstName node, and it is ignored and assigned default value after deserialization. Same for any other types and names (I had node CaseId of Guid type after node Patient of PatientInfo type, and after deserialization it had default value).
I'm serializing it in one application, using next code:
public static string SerializeToString(object data)
{
if (data == null) return null;
XmlSerializerNamespaces ns = new XmlSerializerNamespaces();
ns.Add("", "");
// what should the XmlWriter do?
var settings = new XmlWriterSettings
{
OmitXmlDeclaration = true,
NewLineChars = ""
};
using (var stringwriter = new System.IO.StringWriter())
{
// Use an XmlWriter to wrap the StringWriter
using (var xmlWriter = XmlWriter.Create(stringwriter, settings))
{
var serializer = new XmlSerializer(data.GetType(), "");
// serialize to the XmlWriter instance
serializer.Serialize(xmlWriter, data, ns);
return stringwriter.ToString();
}
}
}
Such approach was used to get proper result as argument for WebMethod (full problem described here). Results are something like this:
<PatientInfo><FirstName>Foo</FirstName><Birthday>2015-12-19T16:21:48.4009949+01:00</Birthday><RequestedClientID>00000000-0000-0000-0000-000000000000</RequestedClientID>00000000-0000-0000-0000-000000000000</patientId></PatientInfo>
Also I'm deserializing it in another application in simple manner
public static T Deserialize<T>(string xmlText)
{
if (String.IsNullOrEmpty(xmlText)) return default(T);
using (var stringReader = new StringReader(xmlText))
{
var serializer = new XmlSerializer(typeof(T));
return (T)serializer.Deserialize(stringReader);
}
}
Example object:
[XmlRoot("PatientInfo")]
public class PatientInfo
{
[XmlElement("FirstName")]
public string FirstName { get; set; }
[XmlElement("LastName")]
public string LastName { get; set; }
[XmlElement("SSN")]
public string SSN { get; set; }
[XmlElement("Birthday")]
public DateTime? Birthday { get; set; }
[XmlElement("RequestedClientID")]
public Guid RequestedClientID { get; set; }
[XmlElement("patientId")]
public Guid patientId { get; set; }
}
So, I'd like to have answer for one of two questions - 1) How can I adjust my serialization to have all items in alphabetical order? 2) How can I adjust my deserialization, so it won't ignore items out of alphabetical order?
Any help is appreciated.
Update:
Just figured out, that deserialization method I'm using is not actually used at all in my problem, since I'm using serialized info as data with WebMethod, and it is deserialized with some internal mechanism of WCF.
WCF uses DataContractSerializer. This serializer is sensitive to XML element order, see Data Member Order. There's no quick way to disable this, instead you need to replace the serializer with XmlSerializer.
To do this, see Using the XmlSerializer Class, then and apply [XmlSerializerFormat] to your service, for instance:
[ServiceContract]
[XmlSerializerFormat]
public interface IPatientInfoService
{
[OperationContract]
public void ProcessPatientInfo(PatientInfo patient)
{
// Code not shown.
}
}
[XmlRoot("PatientInfo")]
public class PatientInfo
{
[XmlElement("FirstName")]
public string FirstName { get; set; }
[XmlElement("LastName")]
public string LastName { get; set; }
[XmlElement("SSN")]
public string SSN { get; set; }
[XmlElement("Birthday")]
public DateTime? Birthday { get; set; }
[XmlElement("RequestedClientID")]
public Guid RequestedClientID { get; set; }
[XmlElement("patientId")]
public Guid patientId { get; set; }
}
We have some configuration files which were generated by serializing C# objects with Json.net.
We'd like to migrate one property of the serialised class away from being a simple enum property into a class property.
One easy way to do this, would be to leave the old enum property on the class, and arrange for Json.net to read this property when we load the config, but not to save it again when we next serialize the object. We'll deal with generating the new class from the old enum separately.
Is there any simple way to mark (e.g. with attributes) a property of a C# object, so that Json.net will ignore it ONLY when serializing, but attend to it when deserializing?
There are actually several fairly simple approaches you can use to achieve the result you want.
Let's assume, for example, that you have your classes currently defined like this:
class Config
{
public Fizz ObsoleteSetting { get; set; }
public Bang ReplacementSetting { get; set; }
}
enum Fizz { Alpha, Beta, Gamma }
class Bang
{
public string Value { get; set; }
}
And you want to do this:
string json = #"{ ""ObsoleteSetting"" : ""Gamma"" }";
// deserialize
Config config = JsonConvert.DeserializeObject<Config>(json);
// migrate
config.ReplacementSetting =
new Bang { Value = config.ObsoleteSetting.ToString() };
// serialize
json = JsonConvert.SerializeObject(config);
Console.WriteLine(json);
To get this:
{"ReplacementSetting":{"Value":"Gamma"}}
Approach 1: Add a ShouldSerialize method
Json.NET has the ability to conditionally serialize properties by looking for corresponding ShouldSerialize methods in the class.
To use this feature, add a boolean ShouldSerializeBlah() method to your class where Blah is replaced with the name of the property that you do not want to serialize. Make the implementation of this method always return false.
class Config
{
public Fizz ObsoleteSetting { get; set; }
public Bang ReplacementSetting { get; set; }
public bool ShouldSerializeObsoleteSetting()
{
return false;
}
}
Note: if you like this approach but you don't want to muddy up the public interface of your class by introducing a ShouldSerialize method, you can use an IContractResolver to do the same thing programmatically. See Conditional Property Serialization in the documentation.
Approach 2: Manipulate the JSON with JObjects
Instead of using JsonConvert.SerializeObject to do the serialization, load the config object into a JObject, then simply remove the unwanted property from the JSON before writing it out. It's just a couple of extra lines of code.
JObject jo = JObject.FromObject(config);
// remove the "ObsoleteSetting" JProperty from its parent
jo["ObsoleteSetting"].Parent.Remove();
json = jo.ToString();
Approach 3: Clever (ab)use of attributes
Apply a [JsonIgnore] attribute to the property that you do not want to be serialized.
Add an alternate, private property setter to the class with the same type as the original property. Make the implementation of that property set the original property.
Apply a [JsonProperty] attribute to the alternate setter, giving it the same JSON name as the original property.
Here is the revised Config class:
class Config
{
[JsonIgnore]
public Fizz ObsoleteSetting { get; set; }
[JsonProperty("ObsoleteSetting")]
private Fizz ObsoleteSettingAlternateSetter
{
// get is intentionally omitted here
set { ObsoleteSetting = value; }
}
public Bang ReplacementSetting { get; set; }
}
For any situation where it's acceptable to have your deserialization-only property be marked internal, there's a remarkably simple solution that doesn't depend on attributes at all. Simply mark the property as internal get, but public set:
public class JsonTest {
public string SomeProperty { internal get; set; }
}
This results in correct deserialization using default settings/resolvers/etc., but the property is stripped from serialized output.
I like sticking with attributes on this one, here is the method I use when needing to deserialize a property but not serialize it or vice versa.
STEP 1 - Create the custom attribute
public class JsonIgnoreSerializationAttribute : Attribute { }
STEP 2 - Create a custom Contract Reslover
class JsonPropertiesResolver : DefaultContractResolver
{
protected override List<MemberInfo> GetSerializableMembers(Type objectType)
{
//Return properties that do NOT have the JsonIgnoreSerializationAttribute
return objectType.GetProperties()
.Where(pi => !Attribute.IsDefined(pi, typeof(JsonIgnoreSerializationAttribute)))
.ToList<MemberInfo>();
}
}
STEP 3 - Add attribute where serialization is not needed but deserialization is
[JsonIgnoreSerialization]
public string Prop1 { get; set; } //Will be skipped when serialized
[JsonIgnoreSerialization]
public string Prop2 { get; set; } //Also will be skipped when serialized
public string Prop3 { get; set; } //Will not be skipped when serialized
STEP 4 - Use it
var sweet = JsonConvert.SerializeObject(myObj, new JsonSerializerSettings { ContractResolver = new JsonPropertiesResolver() });
Hope this helps! Also it's worth noting that this will also ignore the properties when Deserialization happens, when I am derserializing I just use the converter in the conventional way.
JsonConvert.DeserializeObject<MyType>(myString);
Use setter property:
[JsonProperty(nameof(IgnoreOnSerializing))]
public string IgnoreOnSerializingSetter { set { _ignoreOnSerializing = value; } }
[JsonIgnore]
private string _ignoreOnSerializing;
[JsonIgnore]
public string IgnoreOnSerializing
{
get { return this._ignoreOnSerializing; }
set { this._ignoreOnSerializing = value; }
}
Hope this help.
After i spent a quite long time searching how to flag a class property to be De-Serializable and NOT Serializable i found that there's no such thing to do that at all; so i came up with a solution that combines two different libraries or serialization techniques (System.Runtime.Serialization.Json & Newtonsoft.Json) and it worked for me like the following:
flag all your class and sub-classes as "DataContract".
flag all the properties of your class and sub-classes as "DataMember".
flag all the properties of your class and sub-classes as "JsonProperty" except those you want them not to be serialized.
now flag the properties the you do NOT want it to be serialized as "JsonIgnore".
then Serialize using "Newtonsoft.Json.JsonConvert.SerializeObject" and De-Serialize using "System.Runtime.Serialization.Json.DataContractJsonSerializer".
using System;
using System.Collections.Generic;
using Newtonsoft.Json;
using System.Runtime.Serialization;
using System.IO;
using System.Runtime.Serialization.Json;
using System.Text;
namespace LUM_Win.model
{
[DataContract]
public class User
{
public User() { }
public User(String JSONObject)
{
MemoryStream stream = new MemoryStream(Encoding.Unicode.GetBytes(JSONObject));
DataContractJsonSerializer dataContractJsonSerializer = new DataContractJsonSerializer(typeof(User));
User user = (User)dataContractJsonSerializer.ReadObject(stream);
this.ID = user.ID;
this.Country = user.Country;
this.FirstName = user.FirstName;
this.LastName = user.LastName;
this.Nickname = user.Nickname;
this.PhoneNumber = user.PhoneNumber;
this.DisplayPicture = user.DisplayPicture;
this.IsRegistred = user.IsRegistred;
this.IsConfirmed = user.IsConfirmed;
this.VerificationCode = user.VerificationCode;
this.Meetings = user.Meetings;
}
[DataMember(Name = "_id")]
[JsonProperty(PropertyName = "_id")]
public String ID { get; set; }
[DataMember(Name = "country")]
[JsonProperty(PropertyName = "country")]
public String Country { get; set; }
[DataMember(Name = "firstname")]
[JsonProperty(PropertyName = "firstname")]
public String FirstName { get; set; }
[DataMember(Name = "lastname")]
[JsonProperty(PropertyName = "lastname")]
public String LastName { get; set; }
[DataMember(Name = "nickname")]
[JsonProperty(PropertyName = "nickname")]
public String Nickname { get; set; }
[DataMember(Name = "number")]
[JsonProperty(PropertyName = "number")]
public String PhoneNumber { get; set; }
[DataMember(Name = "thumbnail")]
[JsonProperty(PropertyName = "thumbnail")]
public String DisplayPicture { get; set; }
[DataMember(Name = "registered")]
[JsonProperty(PropertyName = "registered")]
public bool IsRegistred { get; set; }
[DataMember(Name = "confirmed")]
[JsonProperty(PropertyName = "confirmed")]
public bool IsConfirmed { get; set; }
[JsonIgnore]
[DataMember(Name = "verification_code")]
public String VerificationCode { get; set; }
[JsonIgnore]
[DataMember(Name = "meeting_ids")]
public List<Meeting> Meetings { get; set; }
public String toJSONString()
{
return JsonConvert.SerializeObject(this, new JsonSerializerSettings() { NullValueHandling = NullValueHandling.Ignore });
}
}
}
Hope that helps ...
Depending on where in the application this takes place and if it's just one property, one manual way you can do this is by setting the property value to null and then on the model you can specify that the property be ignored if the value is null:
[JsonProperty(NullValueHandling = NullValue.Ignore)]
public string MyProperty { get; set; }
If you are working on an ASP.NET Core web app, you can globally set this for all properties in all models by setting this in your Startup.cs file:
public void ConfigureServices(IServiceCollection services) {
// other configuration here
services.AddMvc()
.AddJsonOptions(options => options.SerializerSettings.NullValueHandling = NullValueHandling.Ignore);
}
with reference to #ThoHo's solution, using the setter is actually all that is needed, with no additional tags.
For me I previously had a single reference Id, that I wanted to load and add to the new collection of reference Ids. By changing the definition of the reference Id to only contain a setter method, which added the value to the new collection. Json can't write the value back if the Property doesn't have a get; method.
// Old property that I want to read from Json, but never write again. No getter.
public Guid RefId { set { RefIds.Add(value); } }
// New property that will be in use from now on. Both setter and getter.
public ICollection<Guid> RefIds { get; set; }
This class is now backwards compatible with the previous version and only saves the RefIds for the new versions.
To build upon Tho Ho's answer, this can also be used for fields.
[JsonProperty(nameof(IgnoreOnSerializing))]
public string IgnoreOnSerializingSetter { set { IgnoreOnSerializing = value; } }
[JsonIgnore]
public string IgnoreOnSerializing;
If you use JsonConvert,IgnoreDataMemberAttribute is ok.My standard library not refrence Newton.Json,and I use [IgnoreDataMember] to control object serialize.
From Newton.net help document.
Is there any simple way to mark (e.g. with attributes) a property of a C# object, so that Json.net will ignore it ONLY when serializing, but attend to it when deserializing?
The easiest way I've found as of this writing is to include this logic in your IContractResolver.
Sample code from above link copied here for posterity:
public class Employee
{
public string Name { get; set; }
public Employee Manager { get; set; }
public bool ShouldSerializeManager()
{
// don't serialize the Manager property if an employee is their own manager
return (Manager != this);
}
}
public class ShouldSerializeContractResolver : DefaultContractResolver
{
public new static readonly ShouldSerializeContractResolver Instance = new ShouldSerializeContractResolver();
protected override JsonProperty CreateProperty(MemberInfo member, MemberSerialization memberSerialization)
{
JsonProperty property = base.CreateProperty(member, memberSerialization);
if (property.DeclaringType == typeof(Employee) && property.PropertyName == "Manager")
{
property.ShouldSerialize =
instance =>
{
Employee e = (Employee)instance;
return e.Manager != e;
};
}
return property;
}
}
All of the answers are good but this approach seemed like the cleanest way. I actually implemented this by looking for an attribute on the property for SkipSerialize and SkipDeserialize so you can just mark up any class you control. Great question!
Jraco11's answer is very neat. In case, if you want to use the same IContractResolver both for serialization and deserialization, then you can use the following:
public class JsonPropertiesResolver : DefaultContractResolver
{
protected override JsonProperty CreateProperty(MemberInfo member, MemberSerialization memberSerialization)
{
JsonProperty property = base.CreateProperty(member, memberSerialization);
if (member.IsDefined(typeof(JsonIgnoreSerializationAttribute)))
{
property.ShouldSerialize = instance => false;
}
return property;
}
}
thats will do the trick, create a property with set only
example 1:
https://dotnetfiddle.net/IxMXcG
[JsonProperty("disabled-protections")]
public JArray DisabledProtections { set => IsPartialResult = (value != null && value.HasValues); }
public bool IsPartialResult { get; private set; }
example 2:
private JArray _disabledProtections;
[JsonProperty("disabled-protections")]
public JArray DisabledProtections { set => _disabledProtections = value; }
public bool IsPartialResult => _disabledProtections != null && _disabledProtections.HasValues;
Use [JsonIgnore] attribute in the public property of the model class.
I am receiving the following exception when trying to serialize an object using XMLSerialization.
A circular reference was detected while serializing an object of type MyObject}
I know the circular reference is because ObjectA can have a childObject of ObjectB and ObjectB's parentObject is ObjectA, however I would like to keep that reference if possible . Is there a way to get this object to serialize with XML Serialization without losing any data during the serialization process? I'm not very familar with serialization so I'm hoping theres some kind of Attribute I could set.
There are several options depending on serializer type.
If you could use DataContractSerializer or BinaryFormatter then you may use OnSerializedAttribute and set Parent property for your child object to this:
[Serializable]
public class Child
{
public string Foo { get; set; }
public Parent Parent { get { return parent; } set { parent = value; } }
// We don't want to serialize this property explicitly.
// But we could set it during parent deserialization
[NonSerialized]
private Parent parent;
}
[Serializable]
public class Parent
{
// BinaryFormatter or DataContractSerializer whould call this method
// during deserialization
[OnDeserialized()]
internal void OnSerializedMethod(StreamingContext context)
{
// Setting this as parent property for Child object
Child.Parent = this;
}
public string Boo { get; set; }
public Child Child { get; set; }
}
class Program
{
static void Main(string[] args)
{
Child c = new Child { Foo = "Foo" };
Parent p = new Parent { Boo = "Boo", Child = c };
using (var stream1 = new MemoryStream())
{
DataContractSerializer serializer = new DataContractSerializer(typeof (Parent));
serializer.WriteObject(stream1, p);
stream1.Position = 0;
var p2 = (Parent)serializer.ReadObject(stream1);
Console.WriteLine(object.ReferenceEquals(p, p2)); //return false
Console.WriteLine(p2.Boo); //Prints "Boo"
//Prints: Is Parent not null: True
Console.WriteLine("Is Parent not null: {0}", p2.Child.Parent != null);
}
}
}
If you want to use XmlSerializer you should implement IXmlSerializable, use XmlIgnoreAttribute and implemented more or less the same logic in ReadXml method. But in this case you should also implement all Xml serialization logic manually:
[Serializable]
public class Child
{
public Child()
{
}
public string Foo { get; set; }
[XmlIgnore]
public Parent Parent { get; set; }
}
[Serializable]
public class Parent
{
public Parent()
{
}
#region IXmlSerializable Members
public System.Xml.Schema.XmlSchema GetSchema()
{
throw new NotImplementedException();
}
public void ReadXml(System.Xml.XmlReader reader)
{
//Reading Parent content
//Reading Child
Child.Parent = this;
}
public void WriteXml(System.Xml.XmlWriter writer)
{
//Writing Parent and Child content
}
#endregion
public string Boo { get; set; }
public Child Child { get; set; }
}
If you can use the DataContractSerializer instead of the XMLSerializer then you can use the IsReference property on the DataContract attribute. Enabling this will keep the references, so that they will be recreated upon deserialization.
The DataContractSerializer also serializes to XML, but you have somewhat less control over what the output looks like, that you do with the older XMLSerializer. You can read more about the serializers here: http://www.danrigsby.com/blog/index.php/2008/03/07/xmlserializer-vs-datacontractserializer-serialization-in-wcf/
Mark the parentObject property as [NonSerialized].
https://blog.kowalczyk.info/article/8n/serialization-in-c.html