无法获取多对多表属性的数据

Question

您好，我需要帮助。

我正在使用 ASP.Net Core 3.0 和 EF Core... 我需要编辑一个具有导航属性的多对多表。

我尝试了下面的代码，我可以获取发票数据，但我在 ProductInvoices 属性上得到空值，该属性也是多对多关系表的链接。

        // GET: Invoices/Edit
        public async Task<IActionResult> Edit(int? id)
        {

            var invoice = await _context.Invoices.Where(i => i.InvoiceId == id).FirstOrDefaultAsync();

            return View(invoice);
        }

    public class Product
    {
        [Key]
        public int ProductId { get; set; }

        public int ProductsItemInStock { get; set; }

        public decimal CostPerItem { get; set; }

        public string ItemName { get; set; }

        public IList<ProductInvoice> ProductInvoices { get; set; }
    }


    public class Invoice
    {
        [Key]
        public int InvoiceId { get; set; }

        public DateTime CreatedDate { get; set; }

        public Guid CreateByUser { get; set; }

        public int TotalInvoice { get; set; }

        public IList<ProductInvoice> ProductInvoices { get; set; }
    }
    
        public class ProductInvoice
    {
        [Key]
        public int ProductId { get; set; }
        public Product Product { get; set; }

        [Key]
        public int InvoiceId { get; set; }
        public Invoice Invoice { get; set; }
    }

Answer 1

试试这个

    public async Task<IActionResult> Edit(int? id)
    {

        var invoice = await _context.Invoices.Include("ProductInvoices").Where(i => i.InvoiceId == id).FirstOrDefaultAsync();

        return View(invoice);
    }