实体框架-取代相关实体而不包含

Question

I am developing code first EF6 application and I have one problem with including related entities.

I have model like this:

public class Product
{
    [Key]
    [JsonProperty(Order = 0)]
    [JsonIgnore]
    public int ProductID { get; set; }

    [Required]
    [JsonProperty(Order = 1)]
    public string Name { get; set; }

    [Required]
    [JsonProperty(Order = 2)]
    public virtual Shop Shop { get; set; }

    [Required]
    [JsonProperty(Order = 3)]
    public virtual ProductCategory Category { get; set; }

    [Required]
    [JsonProperty(Order = 4)]
    public double Price { get; set; }

    [JsonProperty(Order = 5)]
    public double? OldPrice { get; set; }
}

My Context has a DBSets like:

public System.Data.Entity.DbSet<PromoCeny.Models.Product> Products { get; set; }

public System.Data.Entity.DbSet<PromoCeny.Models.ProductCategory> ProductCategories { get; set; }

public System.Data.Entity.DbSet<PromoCeny.Models.Shop> Shops { get; set; }

I was trying to access all Product objects like:

db.Products

And I'm getting list of Products but both properties Shop and Category are null

It's strange, but I have one working solution where something like this results proper object(with all properties set properly), but I cannot find difference between these projects.

I was trying to remove virtual flag from properties in model, but this doesn't work also.

Of course I can get list of Products like:

db.Products.Include(product => product.Shop).Include(product => product.Category)

But I would like to avoid that.

Do you know how to handle that?

EDIT:

I have just figured out that i had disabled lazy loading of Entities.

I have removed like:

this.Configuration.LazyLoadingEnabled = false;

from Context and it's working right now.

Answer 1

我相信您需要禁用延迟加载，只要您正确定义了关系，就应该强制链接属性加载。

Answer 2

The behaviour you're experiencing is caused by the lazy-load feature. This can be disabled in your context, like so:

public class MyContext : DbContext 
{ 
    public MyContext() 
    { 
        this.Configuration.LazyLoadingEnabled = false; 
    } 
}

Be aware that this turns off lazy loading for everything; if your object graph is highly interlinked your queries may get very slow as even simple queries can end up loading a lot of data.

Removing the virtual modifier from a collection property should disable lazy loading for that property, but you say it doesn't... To diagnose that, we'd need more info on your EF configuration.