c# - How to serialize a Dictionary as part of its parent object using Json.Net

Question

I'm using Json.Net for serialization. I have a class with a Dictionary:

public class Test
{
    public string X { get; set; }

    public Dictionary<string, string> Y { get; set; }
}

Can I somehow serialize this object to get the following JSON

{
    "X" : "value",
    "key1": "value1",
    "key2": "value2"
}

where "key1", "key2" are keys in the Dictionary?

Answer 1

If you're using Json.Net 5.0.5 or later and you're willing to change the type of your dictionary from Dictionary<string, string> to Dictionary<string, object>, then one easy way to accomplish what you want is to add the [JsonExtensionData] attribute to your dictionary property like this:

public class Test
{
    public string X { get; set; }

    [JsonExtensionData]
    public Dictionary<string, object> Y { get; set; }
}

The keys and values of the marked dictionary will then be serialized as part of the parent object. The bonus is that it works on deserialization as well: any properties in the JSON that do not match to members of the class will be placed into the dictionary.