Reading related data from a member method of the model

Question

I have a model that has some related data in navigation properties, like so:

public class Document
{
        [Key]
        public int DocumentId { get; set; }
        public string DocumentName { get; set; }

        public virtual ICollection<DocumentBeneficiary> DocumentBeneficiaries { get; set; }
        public virtual ICollection<DocumentExecutor> DocumentExecutors { get; set; }
        public virtual ICollection<DocumentSuccessor> DocumentSuccessors { get; set; }
}

I understand how to do eager loading of this related data from a controller method, like so:

var doc = context.Documents.Include(x => x.DocumentBeneficiaries)

However, what I want to do is write a member method inside the model that takes the data related to an entity, does some processing, and outputs a string. Something like this:

public class Document
{
     ...
     public string ProcessStuff() {
         //use data in navigation properties here like so:
         foreach (var d in DocumentBeneficiaries) { ... }
     }
}

Is this allowable? I can't seem to find anything about it on google. Will it load the related data lazy vs. eager depending on how I load the entity in the controller prior to calling the method in the model?

I realize that some schools of thought hold that models should have no methods, but others say it's ok to put business logic in the model. If I have to I suppose I can make this a controller method, but this way makes more sense to my design if possible. Sorry if this is a somewhat speculative question, but I can't seem to find any info on this pattern.

Answer 1

Yes it will load the DocumentBeneficiaries when you invoke ProcessStuff method as long as Lazyloading is enabled, thou it may not be a good design (my opinion) to add business logic directly into the model, but as you stated, there are some who like it and some who don't.

If you don't load the child collection ahead of time using Include and Lazyloading is enabled, then you will end up making extra database trips while executing ProcessStuff(). Using Include pre loads the data you need with less number of database round trips. It is always better to make less database trips whenever possible.

If Lazyloading is disabled, you have to use Include before invoking ProcessStuff()