传递到 ViewDataDictionary 的模型项的类型为“*”，但此 ViewDataDictionary 实例需要“..IEnumerable[*]”类型的模型项

Question

我查看并实施了类似主题的解决方案，但不幸的是他们没有为我提供解决方案。

错误信息：

InvalidOperationException：传递到 ViewDataDictionary 的模型项属于“CMS.Models.Page”类型，但此 ViewDataDictionary 实例需要“System.Collections.Generic.IEnumerable`1[CMS.Models.Page] 类型的模型项'。

我正在开发一个简单的 cms。我的目标是在列出我的页面后对它们进行一些更改。

一段时间以来，我一直在尝试修复该错误，但我无法从我应用的解决方案中获得任何结果。我的猜测是这里的模型结构的数据通信问题。在我的代码下方：

家庭控制器：

    public class HomeController : Controller
{

    private readonly ApplicationDbContext _dbContext;

    public HomeController(ApplicationDbContext dbContext)
    {
        _dbContext = dbContext;
    }

    public IActionResult Index()
    {
        var page = _dbContext.Pages.FirstOrDefault(x => x.Title == "Home");
        return View(page);
    }


    [ResponseCache(Duration = 0, Location = ResponseCacheLocation.None, NoStore = true)]
    public IActionResult Error()
    {
        return View(new ErrorViewModel { RequestId = Activity.Current?.Id ?? HttpContext.TraceIdentifier });
    }
}

管理员控制器：

public class AdminController : Controller
{
    private readonly ApplicationDbContext _context;

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

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

    public async Task<IActionResult> EditPage(string title)
    {
        // SELECT * FROM Pages WHERE Title = {title}
        var page = await _context.Pages.FirstOrDefaultAsync(x => x.Title == title);

        if (page == null)
        {
            page = new Page();
            page.Title = title;

            _context.Pages.Add(page);
            _context.SaveChanges();
        }
        return View(page);
    }

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

        var page = await _context.Pages
            .FirstOrDefaultAsync(m => m.ID == id);
        if (page == null)
        {
            return NotFound();
        }

        return View(page);
    }

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

    // POST: Pages/Create
    // To protect from overposting attacks, 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,Title,Content,Section")] Page page)
    {
        if (ModelState.IsValid)
        {
            _context.Add(page);
            await _context.SaveChangesAsync();
            return RedirectToAction(nameof(Index));
        }
        return View(page);
    }

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

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

    // POST: Pages/Edit/5
    // To protect from overposting attacks, 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,Title,Content,Section")] Page page)
    {
        if (id != page.ID)
        {
            return NotFound();
        }

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

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

        var page = await _context.Pages
            .FirstOrDefaultAsync(m => m.ID == id);
        if (page == null)
        {
            return NotFound();
        }

        return View(page);
    }

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

    private bool PageExists(int id)
    {
        return _context.Pages.Any(e => e.ID == id);
    }
}

我无法查看的页面 => EditPage：

@model IEnumerable<piktusCMS.Models.Page>

@{
    ViewData["Title"] = "Edit Page";
    Layout = "~/Views/Shared/_Layout.cshtml";
}

<h1>Index</h1>

<p>
    <a asp-action="Create">Create New</a>
</p>
<table class="table">
    <thead>
        <tr>
            <th>
                @Html.DisplayNameFor(model => model.Title)
            </th>
            <th>
                @Html.DisplayNameFor(model => model.Content)
            </th>
            <th>
                @Html.DisplayNameFor(model => model.Section)
            </th>
            <th></th>
        </tr>
    </thead>
    <tbody>
        @foreach (var item in Model) {
        <tr>
            <td>
                @Html.DisplayFor(modelItem => item.Title)
            </td>
            <td>
                @Html.DisplayFor(modelItem => item.Content)
            </td>
            <td>
                @Html.DisplayFor(modelItem => item.Section)
            </td>
            <td>
                <a asp-action="Edit" asp-route-id="@item.ID">Edit</a> |
                <a asp-action="Details" asp-route-id="@item.ID">Details</a> |
                <a asp-action="Delete" asp-route-id="@item.ID">Delete</a>
            </td>
        </tr>
}
    </tbody>
</table>

页面模型：

    public class Page
{
    [Key]
    [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
    public int ID { get; set; }

    public string Title { get; set; }

    public string Content { get; set; }

    public string Section { get; set; }
}

数据库上下文：

    public class ApplicationDbContext : IdentityDbContext
{
    public ApplicationDbContext(DbContextOptions<ApplicationDbContext> options)
        : base(options)
    {
    }

    public DbSet<Page> Pages { get; set; }
}

提前感谢您的解决方案和建议

Answer 1

您在 EditPage 中的模型是 IEnumerable<piktusCMS.Models.Page> 类型，但您从 EditPage 操作发送 piktusCMS.Models.Page 类型模型。您只需要在视图页面中更改您的模型。从这个@model IEnumerable<piktusCMS.Models.Page>到这个@model piktusCMS.Models.Page