如何在 LINQ 中执行嵌套一对多连接

Question

如果这很愚蠢，我深表歉意，但在这种情况下如何返回包含 Product 的 IEnumerable：

// Each Receipt can have many ReceiptDetals
public class Receipt
{
    public int Id { get; set; }
    public virtual ICollection<ReceiptDetail> ReceiptDetails { get; set; }  = new List<ReceiptDetail>();
}


// Each ReceiptDetail is related to one Product
public class ReceiptDetail
{
    public int Id { get; set; } 
    // Other properties ....
    public int ProductId { get; set; }   
    public Product Product { get; set; } = new Product();
}

// A Product can be present in none or many ReceiptDetails !!!
public class Product
{
    public int Id { get; set;}  
    // Other properties ...
    public virtual ICollection<ReceiptDetail> ReceiptDetails { get; set; } = new List<ReceiptDetail>();
}

context.Receipt.Include(m => m.ReceiptDetail)

返回

Receipt

的列表，其中包含

ReceiptDetails

，但

Product

内的

ReceiptDetails

为NULL！

此外，

context.Receipt.Include(m => m.ReceiptDetal).Include(x => x.Product)

不起作用，

context.Receipt.Include(m => m.ReceiptDetal.Product)

也不起作用...

我错过了什么？

如有任何建议或帮助，我们将不胜感激！

Answer 1

下面的代码可能适合您。

context.Product.Include(p => p.Receipt).ThenInclude(r => r.ReceiptDetail)