这可能是我想过的一个显而易见的答案,但我需要帮助从共享属性的数据库中检索值。
这个特定的MenuItems数据库包含菜单项和指向我的餐厅数据库的链接。有一个RestaurantID列,代表该项目所属的餐厅。非常简单,但仅举例来说:ID为1的鸡块属于ID为1的餐厅。
我需要执行一个查询,该查询将检索共享相同RestaurantID的菜单项的列表。因此,例如:由于我正在查询RestuarantID == 1的项目,因此它将从数据库中检索9个项目。我在下面的函数中很难选择常用值:
public async Task<IActionResult> GetRestaurantOneVals()
{
int id = 1; //Restuarant one's ID is == 1
var menuItem = await _context.MenuItems
.Include(s => s.Restaurant)
.AsNoTracking()
.FirstOrDefaultAsync(nameof => nameof.Restaurant.ID == id);
var restaurantList = menuItem;
return View(menuItem);
}
这是完整的控制器:
MenuItemsController.cs
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 EasyEats.Data;
using EasyEats.Models;
namespace EasyEats.Controllers
{
public class MenuItemsController : Controller
{
private readonly EasyEatsContext _context;
public MenuItemsController(EasyEatsContext context)
{
_context = context;
}
// GET: MenuItems
public async Task<IActionResult> Index()
{
var easyEatsContext = _context.MenuItems.Include(m => m.Restaurant);
return View(await easyEatsContext.ToListAsync());
}
// GET: MenuItems/Details/5
public async Task<IActionResult> Details(int? id)
{
if (id == null)
{
return NotFound();
}
var menuItem = await _context.MenuItems
.Include(m => m.Restaurant)
.FirstOrDefaultAsync(m => m.ID == id);
if (menuItem == null)
{
return NotFound();
}
return View(menuItem);
}
public async Task<IActionResult> GetRestaurantOneVals()
{
int id = 1; //Restuarant one's ID is == 1
var pleaseGod = await _context.MenuItems
var menuItem = await _context.MenuItems
.Include(s => s.Restaurant)
.AsNoTracking()
.FirstOrDefaultAsync(nameof => nameof.Restaurant.ID == id);
var restaurantList = menuItem;
return View(menuItem);
}
// GET: MenuItems/Create
public IActionResult Create()
{
ViewData["RestaurantID"] = new SelectList(_context.Restaurants, "ID", "ID");
return View();
}
// POST: MenuItems/Create
[HttpPost]
[ValidateAntiForgeryToken]
public async Task<IActionResult> Create([Bind("ID,ItemName,ItemDescription,ItemImagePath,Price,RestaurantID")] MenuItem menuItem)
{
if (ModelState.IsValid)
{
_context.Add(menuItem);
await _context.SaveChangesAsync();
return RedirectToAction(nameof(Index));
}
ViewData["RestaurantID"] = new SelectList(_context.Restaurants, "ID", "ID", menuItem.RestaurantID);
return View(menuItem);
}
// GET: MenuItems/Edit/5
public async Task<IActionResult> Edit(int? id)
{
if (id == null)
{
return NotFound();
}
var menuItem = await _context.MenuItems.FindAsync(id);
if (menuItem == null)
{
return NotFound();
}
ViewData["RestaurantID"] = new SelectList(_context.Restaurants, "ID", "ID", menuItem.RestaurantID);
return View(menuItem);
}
// POST: MenuItems/Edit/5
[HttpPost]
[ValidateAntiForgeryToken]
public async Task<IActionResult> Edit(int id, [Bind("ID,ItemName,ItemDescription,ItemImagePath,Price,RestaurantID")] MenuItem menuItem)
{
if (id != menuItem.ID)
{
return NotFound();
}
if (ModelState.IsValid)
{
try
{
_context.Update(menuItem);
await _context.SaveChangesAsync();
}
catch (DbUpdateConcurrencyException)
{
if (!MenuItemExists(menuItem.ID))
{
return NotFound();
}
else
{
throw;
}
}
return RedirectToAction(nameof(Index));
}
ViewData["RestaurantID"] = new SelectList(_context.Restaurants, "ID", "ID", menuItem.RestaurantID);
return View(menuItem);
}
// GET: MenuItems/Delete/5
public async Task<IActionResult> Delete(int? id)
{
if (id == null)
{
return NotFound();
}
var menuItem = await _context.MenuItems
.Include(m => m.Restaurant)
.FirstOrDefaultAsync(m => m.ID == id);
if (menuItem == null)
{
return NotFound();
}
return View(menuItem);
}
// POST: MenuItems/Delete/5
[HttpPost, ActionName("Delete")]
[ValidateAntiForgeryToken]
public async Task<IActionResult> DeleteConfirmed(int id)
{
var menuItem = await _context.MenuItems.FindAsync(id);
_context.MenuItems.Remove(menuItem);
await _context.SaveChangesAsync();
return RedirectToAction(nameof(Index));
}
private bool MenuItemExists(int id)
{
return _context.MenuItems.Any(e => e.ID == id);
}
}
}
MenuItem.cs模型
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using System.ComponentModel.DataAnnotations;
namespace EasyEats.Models
{
public class MenuItem
{
public int ID { get; set; }
[Display(Name = "Item Name")]
public string ItemName { get; set; }
[Display(Name = "Item Description")]
public string ItemDescription { get; set; }
public string ItemImagePath { get; set; }
public decimal Price { get; set; }
public int RestaurantID { get; set; }
public virtual Restaurant Restaurant { get; set; }
public virtual CartItem CartItem { get; set; }
}
}
您正在使用FirstOrDefaultAsync()
它将检索与给定参数匹配的第一个元素,但是您想返回与参数匹配的整个列表。更改:
var menuItem = await _context.MenuItems
.Include(s => s.Restaurant)
.AsNoTracking()
.FirstOrDefaultAsync(nameof => nameof.Restaurant.ID == id);
为此在您的GetRestaurantOneVals()
方法:
var menuItems = await _context.MenuItems
.Include(s => s.Restaurant)
.AsNoTracking()
.Where(x => x.Restaurant.Id == id)
.ToListAsync();
.Where()
将获取与给定语句匹配的所有对象,并ToList()
创建List<T>
查询外的对象。
然后简单地return View(menuItems);
。
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