How to serialize runtime added “properties” to Json

Question

I implemented the possibility to add \"properties\" at runtime to objects with special SystemComponent.PropertyDescriptor-s.

Due to the fact that these properties ar

Answer 1

One possibility would be to create a custom ContractResolver that, when serializing a specific object of type TTarget, adds a synthetic ExtensionDataGetter that returns, for the specified target, an IEnumerable> of the properties specified in its corresponding DynamicPropertyManager.

First, define the contract resolver as follows:

public class DynamicPropertyContractResolver : DefaultContractResolver
{
    readonly DynamicPropertyManager manager;
    readonly TTarget target;

    public DynamicPropertyContractResolver(DynamicPropertyManager manager, TTarget target)
    {
        if (manager == null)
            throw new ArgumentNullException();
        this.manager = manager;
        this.target = target;
    }

    protected override JsonObjectContract CreateObjectContract(Type objectType)
    {
        var contract = base.CreateObjectContract(objectType);

        if (objectType == typeof(TTarget))
        {
            if (contract.ExtensionDataGetter != null || contract.ExtensionDataSetter != null)
                throw new JsonSerializationException(string.Format("Type {0} already has extension data.", typeof(TTarget)));
            contract.ExtensionDataGetter = (o) =>
                {
                    if (o == (object)target)
                    {
                        return manager.Properties.Select(p => new KeyValuePair(p.Name, p.GetValue(o)));
                    }
                    return null;
                };
            contract.ExtensionDataSetter = (o, key, value) =>
                {
                    if (o == (object)target)
                    {
                        var property = manager.Properties.Where(p => string.Equals(p.Name, key, StringComparison.OrdinalIgnoreCase)).SingleOrDefault();
                        if (property != null)
                        {
                            if (value == null || value.GetType() == property.PropertyType)
                                property.SetValue(o, value);
                            else
                            {
                                var serializer = JsonSerializer.CreateDefault(new JsonSerializerSettings { ContractResolver = this });
                                property.SetValue(o, JToken.FromObject(value, serializer).ToObject(property.PropertyType, serializer));
                            }
                        }
                    }
                };
            contract.ExtensionDataValueType = typeof(object);
        }

        return contract;
    }
}

Then serialize your object as follows:

var obj = new object();

//Add prop to instance
int propVal = 0; 
var propManager = new DynamicPropertyManager