如何确定是否包含相关的儿童实体

Question

I have a web application built with ASP.NET Core / EF Core with two entities "Products" and "ProductOptions" (one-to-many relationship).

When I execute a query to retrieve a Product from the database, is there a way to determine if the related ProductOptions (children of Product) have been included or not? I need to distinguish between the following cases:

Case 1: a Product's related ProductOptions have been included in the query, but no ProductOptions have been found

public Product GetByIdIncludingProductOptions(int id)
{
    return DbContext.Products.Include(p => p.ProductOptions).FirstOrDefault(p => p.Id == id);
}

Case 2: a Product's related ProductOptions haven't been included at all

public Product GetById(int id)
{
    return DbContext.Products.FirstOrDefault(p => p.Id == id);
}

Answer 1

You can use ChangeTracker to check if reference is loaded. You probably want to do something like:

var isLoaded = dbContext.ChangeTracker.Entries<Products>()
    .FirstOrDefault(ee => ee.Entity == product)
    .Reference(e => e.ProductOptions)
    .IsLoaded;