Callback after an object is created

[Kralizek]

I got a class with some properties and a dictionary that contains the value of each property. I'm trying to use a customization to get that nasty dictionary populated with the right values, but the "Do" method gets invoked before the properties are valued. So I got a dictionary with "items" but the items have no value :(

The problem I am experiencing is that "Do" is executed during the object creation, when the properties are not yet populated.

Ideally I would love to have a method that gets executed after the object is created. Something like OnCreate<T>(Action<T>).

This is a sample of class I want get from AutoFixture.

public class Contact : IHubSpotEntity
{
    [DefaultProperty("vid")]
    public long Id { get; set; }

    [CustomProperty("firstname")]
    public string FirstName { get; set; }

    ...

    IReadOnlyDictionary<string, object> IHubSpotEntity.Properties { get; set; } = new Dictionary<string, object>();
}

Here is my attempt to solve the issue with Do<T>(Action<T>)

IFixture fixture = new Fixture();

fixture.Customize<Contact>(c => c.Do(contact =>
{
	((IHubSpotEntity)contact).Properties = new Dictionary<string, object>
	{
		["firstname"] = contact.FirstName,
		["lastname"] = contact.LastName,
		["email"] = contact.Email,
		["createdate"] = contact.Created,
		["associatedcompanyId"] = contact.AssociatedCompanyId
	};
}));

return fixture;

And here is a simple unit test that shows my intended result

[Test, ContactAutoData]
public void Customization_works(Contact contact)
{
    IHubSpotEntity hubSpot = contact;

    Assert.That(contact.FirstName, Is.EqualTo(hubSpot.Properties["firstname"])); // BOOM!
}

where ContactAutoData is a specialization of AutoDataAttribute of AutoFixture.NUnit3 fed with the fixture customized above.

[zvirja]

Hi @Kralizek, thanks for raising this issue.

Unfortunately, currently API doesn't allow you to register callback that is executed after the properties are assigned. It's unlikely that you could somehow work around that using the Customize<> API.

I'm registering that as a potential feature, as current API features are not enough for scenario like this. I do understand that we should not cover all the potential usages, however current scenario looks fundamental.

[Fed03]

I believe this is one of the most useful functionality that are currently missing in an otherwise awesome pkg!