How to exclude property from Json Serialization

Question

I have a DTO class which I Serialize

Json.Serialize(MyClass)

How can I exclude a public property of it?

(It has to

Answer 1

Sorry I decided to write another answer since none of the other answers are copy-pasteable enough.

If you don't want to decorate properties with some attributes, or if you have no access to the class, or if you want to decide what to serialize during runtime, etc. etc. here's how you do it in Newtonsoft.Json

//short helper class to ignore some properties from serialization
public class IgnorePropertiesResolver : DefaultContractResolver
{
    private readonly HashSet ignoreProps;
    public IgnorePropertiesResolver(IEnumerable propNamesToIgnore)
    {
        this.ignoreProps = new HashSet(propNamesToIgnore);
    }

    protected override JsonProperty CreateProperty(MemberInfo member, MemberSerialization memberSerialization)
    {
        JsonProperty property = base.CreateProperty(member, memberSerialization);
        if (this.ignoreProps.Contains(property.PropertyName))
        {
            property.ShouldSerialize = _ => false;
        }
        return property;
    }
}

Usage

JsonConvert.SerializeObject(YourObject, new JsonSerializerSettings()
        { ContractResolver = new IgnorePropertiesResolver(new[] { "Prop1", "Prop2" }) };);

Note: make sure you cache the ContractResolver object if you decide to use this answer, otherwise performance may suffer.

I've published the code here in case anyone wants to add anything

https://github.com/jitbit/JsonIgnoreProps