Wrap primitive type in C# json object serialization and data contract

Question

I'm attempting to strongly type a a string value in a serializable class and I'm having trouble figuring out how to do so.

Below is an example where SomeValue is actually just a string value but I'm attempting to strongly type is to prevent confusion/coding errors with other fields in the same class.

[JsonObject(MemberSerialization.OptIn)]
[DataContract]
public class SomeObject
{
    [DataMember, JsonProperty("some_value")]
    public WrappedString SomeValue { get; set; }
}

The WrappedString class would look something like this:

public class WrappedString
{
    public readonly string Value;

    public WrappedString(string value)
    {
        Value = value;
    }
}

Any thoughts on how to wrap a primitive type and annotate the class that is should use the constructor to deserialize the object?

Answer 1

You can write a custom JsonConverter

var json = @"{""SomeValue"":""x"",""SomeStringValue"":""y""}";
var obj = JsonConvert.DeserializeObject<SomeObject>(json);

---

public class MyConverter : JsonConverter
{

    public override bool CanConvert(Type objectType)
    {
        throw new NotImplementedException();
    }

    public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
    {
        return new WrappedString((string)reader.Value);
    }

    public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
    {
        throw new NotImplementedException();
    }
}

public class SomeObject
{
    [JsonConverter(typeof(MyConverter))]
    public WrappedString SomeValue { get; set; }
    public string SomeStringValue { get; set; }
}

public class WrappedString
{
    public readonly string Value;

    public WrappedString(string value)
    {
        Value = value;
    }
}