Should an input model for creating or updating entities have an ID field to identify the entity, or should your edit action accept an ID parameter?

Compare

Input Model

[HttpPost]
public ActionResult(EntityInputModel input)
{
    var entity = _unitOfWork.CurrenSession.Get<MyEntity>(input.Id);
    // do editing
    // ...
}

Action Parameter

[HttpPost]
public ActionResult(Guid id, EntityInputModel input)
{
    var entity = _unitOfWork.CurrenSession.G开发者_如何学Goet<MyEntity>(id);
    // ...
}

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Personally I prefer the first. I always define a specific view model for each POST action. So if this action requires an id I include it as part of this specific view model.