i'm trying to serialize and deserialize a list of abstract
classes (mustinherit
for vb), obviusly inside it there are only instances of derived classes.
I've decorated the list parameter with the JsonProperty(ItemTypeNameHandling = TypeNameHandling.Auto)
obtaining an output that look like this:
But when i deserialize it keep saying that he cannot deserialize an abstract class.
http://james.newtonking.com/json/help/index.html?topic=html/SerializeTypeNameHandling.htm
public class ConcreteClass
{
private ObservableCollection<AbstractClass> _Nodes = new ObservableCollection<AbstractClass>();
//<Newtonsoft.Json.JsonProperty(itemtypenamehandling:=Newtonsoft.Json.TypeNameHandling.Auto)>
public ObservableCollection<AbstractClass> Nodes {
get { return this._Nodes; }
}
public string Name { get; set; }
public int Id { get; set; }
}
public abstract class AbstractClass
{
private ObservableCollection<AbstractClass> _Nodes = new ObservableCollection<AbstractClass>();
[Newtonsoft.Json.JsonProperty(itemtypenamehandling = Newtonsoft.Json.TypeNameHandling.Auto)]
public ObservableCollection<AbstractClass> Nodes {
get { return this._Nodes; }
}
}
removing the commented line it works!
To serialize a . Net object to JSON string use the Serialize method. It's possible to deserialize JSON string to . Net object using Deserialize<T> or DeserializeObject methods.
By default Newtonsoft does case insensitive JSON deserialization and System. Text. Json does case sensitive JSON deserialization. Case sensitivity comes into play when a JSON string is being deserialized into an object.
Make sure you specify TypeNameHandling when deserializing, as per the docs:
// for security TypeNameHandling is required when deserializing
Stockholder newStockholder = JsonConvert.DeserializeObject<Stockholder>(jsonTypeNameAuto, new JsonSerializerSettings
{
TypeNameHandling = TypeNameHandling.Auto
});
It is worth noting that the documentation is deserializing a Concrete class that contains a collection of Abstract classes.
As an experiment try creating a throw-away class (concrete) that has a single property with your list of abstract objects and see if you can serialize and deserialize that.
UPDATE:
I just tested the following code in LINQPad:
void Main()
{
var test = new List<Business>();
test.Add(new Hotel { Name = "Hilton", Stars = 5 });
test.Add(new Pool { Name = "Big Splash", Capacity = 500 });
test.Dump();
string json = JsonConvert.SerializeObject(test, Newtonsoft.Json.Formatting.Indented, new JsonSerializerSettings
{
TypeNameHandling = TypeNameHandling.All
});
json.Dump();
var businesses = JsonConvert.DeserializeObject<List<Business>>(json, new JsonSerializerSettings
{
TypeNameHandling = TypeNameHandling.All
});
businesses.Dump();
}
// Define other methods and classes here
public abstract class Business
{
public string Name { get;set; }
}
public class Hotel : Business
{
public int Stars { get;set; }
}
public class Pool : Business
{
public int Capacity { get;set;}
}
It worked perfectly. Abstract collection serialized to:
{
"$type": "System.Collections.Generic.List`1[[UserQuery+Business, query_jvrdcu]], mscorlib",
"$values": [
{
"$type": "UserQuery+Hotel, query_jvrdcu",
"Stars": 5,
"Name": "Hilton"
},
{
"$type": "UserQuery+Pool, query_jvrdcu",
"Capacity": 500,
"Name": "Big Splash"
}
]
}
The original and the deserialized collections matched.
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