c# – Display child posts per page

Question:

Good afternoon to everyone who faced such a problem.

There is a table Invoice, it has a child table goods in the invoice. And there is a table of goods.

MVC 5 It was possible to make the following construction on the pages:

@foreach (var item in Model)
{
<tr>
    <td>
        @Html.DisplayFor(modelItem => item.Name)
    </td>
    <td>
        @foreach (var items in item.ListProdukts)
        {

                @Html.DisplayFor(modelItem => items.Produkts.ProduktName)
        }

But in ASP.Net Core it doesn't work. While the studio gives all these fields in the code hints.

Model:

namespace Proba3.Models
{
    public class Invoice
{
    public int InvoiceId { get; set; }
    public string InvoiceName { get; set; }
    public ICollection<ListProdukt> ListProdukts { get; set; }

}
}

namespace Proba3.Models
{
    public class ListProdukt
    {
        public int ListProduktId { get; set; }
        public int ProduktId { get; set; }
        public virtual Produkt Produkts { get; set; }

        public int InvoiceId { get; set; }
        public virtual Invoice Invoices { get; set; }
    }
}

 namespace Proba3.Models
 {
     public class Produkt
     {
        public int ProduktId { get; set; }
        public string ProduktName { get; set; }
        public ICollection<ListProdukt> ListProdukts { get; set; }
    }
}

Controllers:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.Mvc.Rendering;
using Microsoft.EntityFrameworkCore;
using Proba3.Data;
using Proba3.Models;

namespace Proba3.Controllers
{
public class InvoicesController : Controller
{


    private readonly ApplicationDbContext _context;

    public InvoicesController(ApplicationDbContext context)
    {
        _context = context;    
    }

    // GET: Invoices
    public async Task<IActionResult> Index()
    {
       var applicationDbContext = _context.Invoice.Include(c => c.ListProdukts);

        return View(await applicationDbContext.ToListAsync());
    }

Views:

@model IEnumerable<Proba3.Models.Invoice>

@{
    ViewData["Title"] = "Index";
}

<h2>Index</h2>

<p>
    <a asp-action="Create">Create New</a>
</p>
<table class="table">
<thead>
    <tr>
        <th>
            @Html.DisplayNameFor(model => model.InvoiceName)
        </th>
        <th></th>
    </tr>
</thead>
<tbody>
@foreach (var item in Model) {
        <tr>
            <td>
                @Html.DisplayFor(modelItem => item.InvoiceName)
            </td>
            <td>
            @foreach (var items in item.ListProdukts)
            {
                <p>@Html.DisplayFor(modelItem => items.ProduktId)</p>
                <p>@Html.DisplayFor(modelItem => items.Produkts.ProduktName)</p>
            }
            </td>
            <td>

Why doesn't it show ProductName?

Answer:

The answer was given on github.

It turns out ASP.NET Core no longer adds child elements by default. Details can be read in English here: docs.asp.net

In my case, in the Controller you need to add:

to the line:

var applicationDbContext = _context.Invoice.Include(c => c.ListProdukts).ThenInclude(c => c.Produkts);

this:

.ThenInclude(c => c.Produkts);