我在 ASP.NET Core MVC 应用程序中创建或编辑记录时遇到困难

问题描述 投票：0回答：1

我在 ASP.NET Core MVC 应用程序中遇到问题，无法创建或编辑记录。最初，这些操作运行正常。然而，在对膳食模型进行一些修改后，创建和编辑功能不再按预期工作。

这是我的

Meal
模型类：

using System.ComponentModel.DataAnnotations;

namespace Caloracker1.Models
{
    public class Meal
    {
        [Key]
        public int Id { get; set; }

        public string? Name { get; set; }
        public double? TotalCalorie { get; set; }
        public double? Amount { get; set; }
        public string? ImageUrl { get; set; }
        public string? Description { get; set; }
        public double? Carbonhydrate { get; set; }
        public double? Protein { get; set; }
        public double? Fat { get; set; }
    }
}

我的

MealController
：

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 Caloracker1.Data;
using Caloracker1.Models;

namespace Caloracker1.Views
{
    public class MealsController : Controller
    {
        private readonly Caloracker1Context _context;

        public MealsController(Caloracker1Context context)
        {
            _context = context;
        }

        // GET: Meals
        public async Task<IActionResult> Index()
        {
            return View(await _context.Meal.ToListAsync());
        }

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

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

            return View(meal);
        }

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

        // POST: Meals/Create
        [HttpPost]
        [ValidateAntiForgeryToken]
        public async Task<IActionResult> Create([Bind("Id,Name,TotalCalorie,Amount,ImageUrl,Description,Carbonhydrate,Protein,Fat")] Meal meal)
        {
            if (ModelState.IsValid)
            {
                _context.Add(meal);
                await _context.SaveChangesAsync();
                return RedirectToAction(nameof(Index));
            }

            return View(meal);
        }

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

            var meal = await _context.Meal.FindAsync(id);

            if (meal == null)
            {
                return NotFound();
            }

            return View(meal);
        }

        // POST: Meals/Edit/5
        [HttpPost]
        [ValidateAntiForgeryToken]
        public async Task<IActionResult> Edit(int id, [Bind("Id,Name,TotalCalorie,Amount,ImageUrl,Description,Carbonhydrate,Protein,Fat")] Meal meal)
        {
            if (id != meal.Id)
            {
                return NotFound();
            }

            if (ModelState.IsValid)
            {
                try
                {
                    _context.Update(meal);
                    await _context.SaveChangesAsync();
                }
                catch (DbUpdateConcurrencyException)
                {
                    if (!MealExists(meal.Id))
                    {
                        return NotFound();
                    }
                    else
                    {
                        throw;
                    }
                }

                return RedirectToAction(nameof(Index));
            }

            return View(meal);
        }

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

            var meal = await _context.Meal
                                     .FirstOrDefaultAsync(m => m.Id == id);

            if (meal == null)
            {
                return NotFound();
            }

            return View(meal);
        }

        // POST: Meals/Delete/5
        [HttpPost, ActionName("Delete")]
        [ValidateAntiForgeryToken]
        public async Task<IActionResult> DeleteConfirmed(int id)
        {
            var meal = await _context.Meal.FindAsync(id);

            if (meal != null)
            {
                _context.Meal.Remove(meal);
            }

            await _context.SaveChangesAsync();

            return RedirectToAction(nameof(Index));
        }

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

以及我的创建和编辑视图

创建

@model Caloracker1.Models.Meal

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

<h1>Create</h1>

<h4>Meal</h4>
<hr />
<div class="row">
    <div class="col-md-4">
        <form asp-action="Create">
            <div asp-validation-summary="ModelOnly" class="text-danger"></div>
            <div class="form-group">
                <label asp-for="Name" class="control-label"></label>
                <input asp-for="Name" class="form-control" />
                <span asp-validation-for="Name" class="text-danger"></span>
            </div>
            <div class="form-group">
                <label asp-for="TotalCalorie" class="control-label"></label>
                <input asp-for="TotalCalorie" class="form-control" />
                <span asp-validation-for="TotalCalorie" class="text-danger"></span>
            </div>
            <div class="form-group">
                <label asp-for="Amount" class="control-label"></label>
                <input asp-for="Amount" class="form-control" />
                <span asp-validation-for="Amount" class="text-danger"></span>
            </div>
            <div class="form-group">
                <label asp-for="ImageUrl" class="control-label"></label>
                <input asp-for="ImageUrl" class="form-control" />
                <span asp-validation-for="ImageUrl" class="text-danger"></span>
            </div>
            <div class="form-group">
                <label asp-for="Description" class="control-label"></label>
                <input asp-for="Description" class="form-control" />
                <span asp-validation-for="Description" class="text-danger"></span>
            </div>
            <div class="form-group">
                <label asp-for="Carbonhydrate" class="control-label"></label>
                <input asp-for="Carbonhydrate" class="form-control" />
                <span asp-validation-for="Carbonhydrate" class="text-danger"></span>
            </div>
            <div class="form-group">
                <label asp-for="Protein" class="control-label"></label>
                <input asp-for="Protein" class="form-control" />
                <span asp-validation-for="Protein" class="text-danger"></span>
            </div>
            <div class="form-group">
                <label asp-for="Fat" class="control-label"></label>
                <input asp-for="Fat" class="form-control" />
                <span asp-validation-for="Fat" class="text-danger"></span>
            </div>
            <div class="form-group">
                <input type="submit" value="Create" class="btn btn-primary" />
            </div>
        </form>
    </div>
</div>

<div>
    <a asp-action="Index">Back to List</a>
</div>

@section Scripts {
    @{
        await Html.RenderPartialAsync("_ValidationScriptsPartial");
    }
}

编辑

@model Caloracker1.Models.Meal

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

<h1>Edit</h1>

<h4>Meal</h4>
<hr />
<div class="row">
    <div class="col-md-4">
        <form asp-action="Edit">
            <div asp-validation-summary="ModelOnly" class="text-danger"></div>
            <input type="hidden" asp-for="Id" />
            <div class="form-group">
                <label asp-for="Name" class="control-label"></label>
                <input asp-for="Name" class="form-control" />
                <span asp-validation-for="Name" class="text-danger"></span>
            </div>
            <div class="form-group">
                <label asp-for="TotalCalorie" class="control-label"></label>
                <input asp-for="TotalCalorie" class="form-control" />
                <span asp-validation-for="TotalCalorie" class="text-danger"></span>
            </div>
            <div class="form-group">
                <label asp-for="Amount" class="control-label"></label>
                <input asp-for="Amount" class="form-control" />
                <span asp-validation-for="Amount" class="text-danger"></span>
            </div>
            <div class="form-group">
                <label asp-for="ImageUrl" class="control-label"></label>
                <input asp-for="ImageUrl" class="form-control" />
                <span asp-validation-for="ImageUrl" class="text-danger"></span>
            </div>
            <div class="form-group">
                <label asp-for="Description" class="control-label"></label>
                <input asp-for="Description" class="form-control" />
                <span asp-validation-for="Description" class="text-danger"></span>
            </div>
            <div class="form-group">
                <label asp-for="Carbonhydrate" class="control-label"></label>
                <input asp-for="Carbonhydrate" class="form-control" />
                <span asp-validation-for="Carbonhydrate" class="text-danger"></span>
            </div>
            <div class="form-group">
                <label asp-for="Protein" class="control-label"></label>
                <input asp-for="Protein" class="form-control" />
                <span asp-validation-for="Protein" class="text-danger"></span>
            </div>
            <div class="form-group">
                <label asp-for="Fat" class="control-label"></label>
                <input asp-for="Fat" class="form-control" />
                <span asp-validation-for="Fat" class="text-danger"></span>
            </div>
            <div class="form-group">
                <input type="submit" value="Save" class="btn btn-primary" />
            </div>
        </form>
    </div>
</div>

<div>
    <a asp-action="Index">Back to List</a>
</div>

@section Scripts {
    @{
        await Html.RenderPartialAsync("_ValidationScriptsPartial");
    }
}

此外，我还提供了 

MealsController
的相关部分以及用于创建和编辑操作的相关视图。

尽管进行了这些更改，创建和编辑操作仍无法按预期进行。任何解决此问题的见解或建议将不胜感激。

asp.net-core asp.net-core-mvc
1个回答
0
投票

对膳食模型进行一些修改后，创建和编辑功能不再按预期工作。

请注意，每次模型更改时，它都会与数据库不同步。

您可以通过以下步骤进行迁移并将更新应用到数据库：

PM> 添加迁移新更新

PM>更新数据库

有关 EF Core 迁移的更多信息，请查看此文档：https://learn.microsoft.com/en-us/ef/core/managing-schemas/migrations/?tabs=vs

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