Navigation property is NULL after insert in Entity Framework

Question

I saw this post that suggests an answer but my situation is a bit different.

// Create a new Lunch entity with these two properties.
Lunch lunchEntity = new LunchEntity();
lunchEntity.UserId = userId;
lunchEntity.MealId = mealId;

// Add the entity to the DbContext and save the changes.
restaurantEntities.Lunches.Add(lunchEntity);
restaurantEntities.SaveChanges();

// Get the Lunch entity that we inserted above.
Lunch mySavedLunchEntity = restaurantEntities.Lunches.Find(lunchEntity.Id);

Now, after inserting the Lunch entity, I need to have its instance with all of its navigation properties included. That's why I use the Find() method to select the newly created entity. The problem is that the User navigation property is null, while the Meal navigation property has a reference to the correct object.

Moreover, if I execute this statement

Lunch mySavedLunchEntity = restaurantEntities.Lunches.Find(lunchId);

separately in another method that is supposed to retrieve a Lunch entity for a particular Id, all navigation properties are included correctly.

So, my question is why all my navigation properties are included when I just query a given element, and some of them are not, if I query the element only after it has been inserted?

Answer 1

You could try:

Lunch mySavedLunchEntity = restaurantEntities.Lunches.Where(l => l.LunchId == lunchId).Include(l => l.User).Include(l => l.Meal)

This forces EF to load the two navigation properties instead of Lazy loading them.