I would like to use JSON.net to deserialize to an object but put unmapped properties in a dictionary property. Is it possible?
For example given the json,
{one:1,two:2,three:3}
and the c# class:
public class Mapped {
public int One {get; set;}
public int Two {get; set;}
public Dictionary<string,object> TheRest {get; set;}
}
Can JSON.NET deserialize to an instance with values one=1, two=1, TheRest= Dictionary{{"three,3}}
The easiest way to do this is to use the JsonExtensionData attribute to define a catch all dictionary.
Example from the Json.Net documentation:
public class DirectoryAccount
{
// normal deserialization
public string DisplayName { get; set; }
// these properties are set in OnDeserialized
public string UserName { get; set; }
public string Domain { get; set; }
[JsonExtensionData]
private IDictionary<string, JToken> _additionalData;
[OnDeserialized]
private void OnDeserialized(StreamingContext context)
{
// SAMAccountName is not deserialized to any property
// and so it is added to the extension data dictionary
string samAccountName = (string)_additionalData["SAMAccountName"];
Domain = samAccountName.Split('\\')[0];
UserName = samAccountName.Split('\\')[1];
}
public DirectoryAccount()
{
_additionalData = new Dictionary<string, JToken>();
}
}
string json = @"{
'DisplayName': 'John Smith',
'SAMAccountName': 'contoso\\johns'
}";
DirectoryAccount account = JsonConvert.DeserializeObject<DirectoryAccount>(json);
Console.WriteLine(account.DisplayName);
// John Smith
Console.WriteLine(account.Domain);
// contoso
Console.WriteLine(account.UserName);
// johns
You can create a CustomCreationConverter to do what you need to do. Here's a sample (rather ugly, but demonstrates how you may want to go about this):
namespace JsonConverterTest1
{
public class Mapped
{
private Dictionary<string, object> _theRest = new Dictionary<string, object>();
public int One { get; set; }
public int Two { get; set; }
public Dictionary<string, object> TheRest { get { return _theRest; } }
}
public class MappedConverter : CustomCreationConverter<Mapped>
{
public override Mapped Create(Type objectType)
{
return new Mapped();
}
public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
{
var mappedObj = new Mapped();
var objProps = objectType.GetProperties().Select(p => p.Name.ToLower()).ToArray();
//return base.ReadJson(reader, objectType, existingValue, serializer);
while (reader.Read())
{
if (reader.TokenType == JsonToken.PropertyName)
{
string readerValue = reader.Value.ToString().ToLower();
if (reader.Read())
{
if (objProps.Contains(readerValue))
{
PropertyInfo pi = mappedObj.GetType().GetProperty(readerValue, BindingFlags.IgnoreCase | BindingFlags.Public | BindingFlags.Instance);
var convertedValue = Convert.ChangeType(reader.Value, pi.PropertyType);
pi.SetValue(mappedObj, convertedValue, null);
}
else
{
mappedObj.TheRest.Add(readerValue, reader.Value);
}
}
}
}
return mappedObj;
}
}
public class Program
{
static void Main(string[] args)
{
string json = "{'one':1, 'two':2, 'three':3, 'four':4}";
Mapped mappedObj = JsonConvert.DeserializeObject<Mapped>(json, new MappedConverter());
Console.WriteLine(mappedObj.TheRest["three"].ToString());
Console.WriteLine(mappedObj.TheRest["four"].ToString());
}
}
}
So the output of mappedObj after you deserialize the JSON string will be an object with its One and Two properties populated, and everything else put into the Dictionary. Granted, I hard-coded the One and Two values as ints, but I think this demonstrates how you'd go about this.
I hope this helps.
EDIT: I updated the code to make it more generic. I didn't fully test it out, so there may some cases where it fails, but I think it gets you most of the way there.
