Register IPreUpdateEventListeners only on Entity object

[geoffreysmith]

Should be possible to throw something like this in:

    var entity = @event.Entity as IValidatableObject;
    if (entity == null)
        return false

[shatl]

As I understand it can validate any object, so
Validator.ValidateObject(@event.Entity, new ValidationContext(entity, null, null), true); should also work

[dwick]

ValidatableObject also needs to implement IValidatableObject for geoffrey's change to work

[alecwhittington]

This has been corrected. Closing comments unless someone needs to open it back up.

[MartinHornagold]

This was fixed for OnPreUpdate but not OnPreInsert

OnPreInsert still has the cast to Entity as shown below:
var entity = (Entity)@event.Entity;