ContractResolver.md

Serialization using ContractResolver

The Argon.IContractResolver interface provides a way to customize how the JsonSerializer serializes and deserializes .NET objects to JSON without placing attributes on classes.

Anything that can be set on an object, collection, property, etc, using attributes or methods to control serialization can also be set using an IContractResolver.

For performance create a contract resolver once and reuse instances when possible. Resolving contracts is slow and implementations of Argon.IContractResolver typically cache contracts.

DefaultContractResolver

The Argon.DefaultContractResolver is the default resolver used by the serializer. It provides many avenues of extensibility in the form of virtual methods that can be overridden.

CamelCasePropertyNamesContractResolver

Argon.CamelCasePropertyNamesContractResolver inherits from DefaultContractResolver and overrides the JSON property name to be written in camelcase.

var product = new Product
{
    ExpiryDate = new(2010, 12, 20, 18, 1, 0, DateTimeKind.Utc),
    Name = "Widget",
    Price = 9.99m,
    Sizes = ["Small", "Medium", "Large"]
};

var json =
    JsonConvert.SerializeObject(
        product,
        Formatting.Indented,
        new JsonSerializerSettings {ContractResolver = new CamelCasePropertyNamesContractResolver()}
    );

//{
//  "name": "Widget",
//  "expiryDate": "2010-12-20T18:01:00Z",
//  "price": 9.99,
//  "sizes": [
//    "Small",
//    "Medium",
//    "Large"
//  ]
//}

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Custom IContractResolver Examples

TODO:

public class ConverterContractResolver : DefaultContractResolver
{
    public new static readonly ConverterContractResolver Instance = new();

    protected override JsonContract CreateContract(Type type)
    {
        var contract = base.CreateContract(type);

        // this will only be called once and then cached
        if (type == typeof(DateTime) || type == typeof(DateTimeOffset))
        {
            contract.Converter = new JavaScriptDateTimeConverter();
        }

        return contract;
    }
}