如何從控制器向數據庫添加兩個特定值？

Question

在下面的代碼中，我試圖獲取當前登錄用戶的用戶名以及他們要訂購的商品的詳細信息，但是由於我根本不知道將用戶名和所選商品同時添加到數據庫中，因此無法正常工作數據庫。

[HttpPost]
        public async Task<IActionResult> AddOrder([Bind("Id,Name,Location,Price,Description")] Order order)
        { 
            var user = _userManager.GetUserName(User);

            if (ModelState.IsValid)
            {
                _context.Add(order + user);
                await _context.SaveChangesAsync();
                return RedirectToAction(nameof(Index));
            }
            return View(order);
        } 

我將如何實現此功能的任何幫助將不勝感激。 （下面是我項目中的更多代碼）

我的整個PackagesController

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 JTMajorProject.DataAccess.Models;
using JTMajorProject.Models;
using JTMajorProject.DataAccess;
using Microsoft.AspNetCore.Identity;

namespace JTMajorProject.Controllers
{
    //[Route("/packages")]
    public class PackagesController : Controller
    {
        private readonly JTMajorProjectContext _context;
        private readonly UserManager<IdentityUser> _userManager;

        public PackagesController(JTMajorProjectContext context, UserManager<IdentityUser> userManager)
        {
            _context = context;
            _userManager = userManager;
        }


        // GET: Packages
        public async Task<IActionResult> Index(string searchString, string searchLocation)
        {

            var packages = from p in _context.Package
                         select p;

            if (!String.IsNullOrEmpty(searchString))
            {
                packages = packages.Where(s => s.Name.Contains(searchString));
            }

            if (!String.IsNullOrEmpty(searchLocation))
            {
                packages = packages.Where(s => s.Location.Contains(searchLocation));
            } 

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

        // GET: Packages/Details/5
        public async Task<IActionResult> Details(int? id)
        {
            if (id == null)
            {   
                return NotFound(); 
            } 

            var package = await _context.Package
                .FirstOrDefaultAsync(m => m.Id == id);
            if (package == null)
            {
                return NotFound();
            }

            return View(package);
        }

        public async Task<IActionResult> Order(int? id)
        {
            if (id == null)
            {
                return NotFound();
            }

            var package = await _context.Package
                .FirstOrDefaultAsync(m => m.Id == id);
            if (package == null)
            {
                return NotFound();
            }

            return View(package);
        }

        // GET: Packages/Create
        public IActionResult Create()
        {
            return View();
        }

        // POST: Packages/Create
        // To protect from overposting attacks, please enable the specific properties you want to bind to, for 
        // more details see http://go.microsoft.com/fwlink/?LinkId=317598. 
        [HttpPost]
        [ValidateAntiForgeryToken]
        public async Task<IActionResult> Create([Bind("Id,Name,Location,Price,Description")] Package package)
        {
            if (ModelState.IsValid)
            {
                _context.Add(package);
                await _context.SaveChangesAsync();
                return RedirectToAction(nameof(Index));
            }
            return View(package);
        }

        [HttpPost]
        public async Task<IActionResult> AddOrder([Bind("Id,Name,Location,Price,Description")] Order order)
        { 
            var user = _userManager.GetUserName(User);

            if (ModelState.IsValid)
            {
                _context.Add(order + user);
                await _context.SaveChangesAsync();
                return RedirectToAction(nameof(Index));
            }
            return View(order);
        }

        // GET: Packages/Edit/5
        public async Task<IActionResult> Edit(int? id)
        {
            if (id == null)
            {
                return NotFound();
            }

            var package = await _context.Package.FindAsync(id);
            if (package == null)
            {
                return NotFound();
            }
            return View(package);
        }

        // POST: Packages/Edit/5
        // To protect from overposting attacks, please enable the specific properties you want to bind to, for 
        // more details see http://go.microsoft.com/fwlink/?LinkId=317598.
        [HttpPost]
        [ValidateAntiForgeryToken]
        public async Task<IActionResult> Edit(int id, [Bind("Id,Name,Location,Price,Description")] Package package)
        {
            if (id != package.Id)
            {
                return NotFound();
            }

            if (ModelState.IsValid)
            {
                try
                {
                    _context.Update(package);
                    await _context.SaveChangesAsync();
                }
                catch (DbUpdateConcurrencyException)
                {
                    if (!PackageExists(package.Id))
                    {
                        return NotFound();
                    }
                    else
                    {
                        throw;
                    }
                }
                return RedirectToAction(nameof(Index));
            }
            return View(package);
        }

        // GET: Packages/Delete/5
        public async Task<IActionResult> Delete(int? id)
        {
            if (id == null)
            {
                return NotFound();
            }

            var package = await _context.Package
                .FirstOrDefaultAsync(m => m.Id == id);
            if (package == null)
            {
                return NotFound();
            }

            return View(package);
        }

        // POST: Packages/Delete/5
        [HttpPost, ActionName("Delete")]
        [ValidateAntiForgeryToken]
        public async Task<IActionResult> DeleteConfirmed(int id)
        {
            var package = await _context.Package.FindAsync(id);
            _context.Package.Remove(package);
            await _context.SaveChangesAsync();
            return RedirectToAction(nameof(Index));
        }

        private bool PackageExists(int id)
        {
            return _context.Package.Any(e => e.Id == id);
        }
    }
}

用於訂購過程的Razor頁面，該頁面具有將數據發送到控制器的形式

@using Microsoft.AspNetCore.Identity
@inject SignInManager<IdentityUser> SignInManager
@inject UserManager<IdentityUser> UserManager
@using System.Security.Claims

@model JTMajorProject.DataAccess.Models.Package

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

<div>
    <section style="background-color: black; height: 150px; width: 1520px"></section>
</div>
<div class="row">
    <div class="col-md-4">
        <form asp-action="AddOrder"> 
            <input type="hidden" asp-for="Id" />
            <h1 style="margin-top:50px">Your Order: </h1>

            <div style="margin: 20px;">
                <h4>
                    Account - @if (SignInManager.IsSignedIn(User))
                    {
                        <a id="manage" class="text-black" asp-area="Identity" asp-page="/Account/Manage/Index" title="Manage" style="color: black">
                            @UserManager.GetUserName(User)
                        </a>
                    }
                    else
                    {
                        <a style="margin:20px">Currently not signed in.</a>
                    }
                </h4>
            </div>


            <div style="margin: 30px">
                <h4 style="margin-top: 50px;">Package</h4>
                <hr />
                <dl class="row">
                    <dt class="col-sm-2">
                        @Html.DisplayNameFor(model => model.Name)
                    </dt>
                    <dd class="col-sm-10">
                        @Html.DisplayFor(model => model.Name)
                    </dd>
                    <dt class="col-sm-2">
                        @Html.DisplayNameFor(model => model.Location)
                    </dt>
                    <dd class="col-sm-10">
                        @Html.DisplayFor(model => model.Location)
                    </dd>
                    <dt class="col-sm-2">
                        @Html.DisplayNameFor(model => model.Price)
                    </dt>
                    <dd class="col-sm-10">
                        @Html.DisplayFor(model => model.Price)
                    </dd>
                    <dt class="col-sm-2">
                        @Html.DisplayNameFor(model => model.Description)
                    </dt>
                    <dd class="col-sm-10">
                        @Html.DisplayFor(model => model.Description)
                    </dd>
                </dl>
            </div>
            @if (SignInManager.IsSignedIn(User))
            {
                <div style="margin: 30px">
                    <button type="submit">Confirm Order</button>
                </div>
            }
            else
            {
                <a style="margin:30px; font-weight:bold; font-size: 25px;">Please sign in to purchase this order.</a>
            }

    </form>
        </div>
    </div>
            <div style="margin: 30px">
                <a asp-action="Index">Back to Package List</a>
            </div>

Answer 1

似乎您正在嘗試在IdentityUser表和Order表之間建立一對多關系。 為此，您在定義Order模型時需要添加外鍵。

public class Order
{
    [Key]
    public string Id { get; set; }
    public string Name { get; set; }
    public string Location { get; set; }
    public double Price { get; set; }
    public string Description { get; set; }

    //This sets the relation
    public string IdentityUserId {get; set; }
    [ForeignKey("IdentityUserId ")]
    public IdentityUser IdentityUser { get; set; }
}

有關ASP中關系的更多信息： https : //docs.microsoft.com/zh-cn/ef/core/modeling/relationships

一旦建立了關系，您應該能夠使用FK將訂單添加到表中，該FK將訂單鏈接到創建訂單的用戶。 您的控制器應如下所示：

[HttpPost]
public async Task<IActionResult> AddOrder([Bind("Id,Name,Location,Price,Description")] Order order)
{ 
    //Gets the ID of the currently logged user
    string userId = _userManager.GetUserId(HttpContext.User);

    if (ModelState.IsValid)
    {
        var newOrder = New Order
        {
            Id = order.Id,
            Name = order.Name,
            Location = order.Location,
            Price = order.Price,
            Description = order.Description,

            //Here you make the relation between the order and the user that made it
            IdentityUserId = userId
        }

        _context.Add(newOrder);
        await _context.SaveChangesAsync();
        return RedirectToAction(nameof(Index));
    }
    return View(order);
}