[Deserialization] Scalar or Object

[Oleexo]

Hi guys,

I try to deserialize somethings like that:

test:
  key1:
     property1: p1
     property2: p2
  key2:
     property1: p1
     property2: p2

So I created a class like this:

public class Root {
  public Dictionnary<string, MyCustomObject> Test { get; set; }
}

public class MyCustomObject {
   public string Property1 { get; set; }
   public string Property2 { get; set; }
}

until here everythings is ok BUT ! The yaml can also be written like that:

test:
  key1: p1
  key2:
     property1: p1
     property2: p2

In this case, the instance of MyCustomObject with the key 'key1' have for values: Property1 = p1 and Property2 = Some default value.
I have a very long yaml file with many situation like this. I can't find an option for intercept this case and create a little pieces of code to handle the case:
=> IsScalar so the scalar property goes here in the object
=> IsObject so deserialize with the default class and configuration

If you have have any clue how I can create a behavior like that without recreating the property mapper ?

Thanks !

[EdwardCooke]

I know this is old, but here's a potential answer, you can create a YamlTypeConverter class that takes the tokens from the YAML stream and parses them in to an object. If the token is a scalar, set your single property and return the object, else if it is a mappingstart, read through them in an alternating key/value pair of scalars. It's not the cleanest solution, but it might work for what you are looking to do.

An example of such a converter is this:

using YamlDotNet.Core;
using YamlDotNet.Core.Events;
using YamlDotNet.Serialization;

public class MyCustomObjectTypeConverter : IYamlTypeConverter
{
    public bool Accepts(Type type)
    {
        return type == typeof(MyCustomObject);
    }

    public object? ReadYaml(IParser parser, Type type)
    {
        if (parser.TryConsume<Scalar>(out var scalar))
        {
            var result = new MyCustomObject
            {
                Property1 = scalar.Value
            };
            return result;
        }
        else if (parser.TryConsume<MappingStart>(out var _))
        {
            var result = new MyCustomObject();
            while (!(parser.Current is MappingEnd))
            {
                //key
                var key = parser.Consume<Scalar>();
                var value = parser.Consume<Scalar>();
                switch (key.Value.ToLowerInvariant())
                {
                    case "property1":
                        result.Property1 = value.Value;
                        break;
                    case "property2":
                        result.Property2 = value.Value;
                        break;
                }
            }
            parser.Consume<MappingEnd>();
            return result;
        }
        return null;
    }

    public void WriteYaml(IEmitter emitter, object? value, Type type)
    {
        throw new NotImplementedException();
    }
}

I'm closing the issue, but if you need further help, let me know.