ASP.NET MVC中SQL Server数据删除404错误排查与解决

问题背景 #

开发ASP.NET MVC应用时，涉及AvailableDates和Bookings两张SQL Server数据表。用户在UI选择日期删除预订时，需删除Bookings表中对应（包含所选日期、提交日期、用户名）的行。已实现“确认取消预订”按钮，但点击后触发404错误：无法找到网页https://localhost:44355/Booking/ConfirmCancelBooking。需解决该404错误，并确保ConfirmCancelBooking动作正确处理删除流程。

模型代码 #

public class AvailableDate
{
    public int Id { get; set; }
    public DateTime Date { get; set; }
}

public class Booking
{
    public int Id { get; set; }
    public string Username { get; set; }
    public DateTime SelectedDate { get; set; }
    public DateTime SubmissionDate { get; set; }
}

控制器代码 #

public class BookingController : Controller
{
    private readonly MyDbContext _context;

    public BookingController(MyDbContext context)
    {
        _context = context;
    }

    public IActionResult CancelBooking(int bookingId)
    {
        string fullUsername = User.Identity.Name; 

        var booking = _context.Bookings.SingleOrDefault(b => b.Id == bookingId && b.Username == fullUsername);

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

        return View(booking);
    }

    [HttpPost]
    public IActionResult ConfirmCancelBooking(int bookingId)
    {
        string fullUsername = User.Identity.Name; 

        var booking = _context.Bookings.SingleOrDefault(b => b.Id == bookingId 
                                                             && b.Username == fullUsername);

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

        _context.Bookings.Remove(booking);
        _context.SaveChanges();

        return RedirectToAction("Index");
    }
}

视图代码 #

@{
    ViewBag.Title = "Cancel Booking";
}

<h2>Cancel Booking</h2>

<p>Are you sure you want to cancel your booking for @Model.SelectedDate?</p>

@using (Html.BeginForm("ConfirmCancelBooking", "Booking", FormMethod.Post))
{
    @Html.HiddenFor(model => model.Id)
    <input type="submit" value="Confirm Cancellation" class="btn btn-danger" />
    <a href="@Url.Action("Index", "Booking")" class="btn btn-secondary">Back to Bookings</a>
}

一、修复404错误 #

1. 修正参数名称不匹配问题 #

视图通过@Html.HiddenFor(model => model.Id)传递的参数是Id，但控制器ConfirmCancelBooking方法接收的参数名是bookingId，参数名不匹配导致路由无法找到对应动作。

两种修复方式：

• 方式一：修改控制器方法参数名，与视图传递的参数名一致

[HttpPost]
public IActionResult ConfirmCancelBooking(int id) // 将bookingId改为id
{
    string fullUsername = User.Identity.Name; 
    var booking = _context.Bookings.SingleOrDefault(b => b.Id == id 
                                                         && b.Username == fullUsername);
    // 其余逻辑不变
}

• 方式二：修改视图隐藏字段，指定参数名为bookingId

@Html.Hidden("bookingId", Model.Id)

2. 检查路由配置 #

确认项目路由配置正确启用控制器路由（以ASP.NET Core 6+为例，在Program.cs中）：

app.MapControllerRoute(
    name: "default",
    pattern: "{controller=Home}/{action=Index}/{id?}");

若控制器在自定义命名空间下，需在路由中指定命名空间：

app.MapControllerRoute(
    name: "default",
    pattern: "{controller=Home}/{action=Index}/{id?}",
    namespaces: new[] { "YourApp.Controllers" });

3. 验证控制器命名规范 #

确保控制器类名为BookingController（必须以Controller为后缀），且所在命名空间被项目扫描覆盖。

二、确保删除流程正确 #

1. 优化数据查询逻辑 #

用FirstOrDefault替代SingleOrDefault，避免因数据库存在重复记录时抛出异常：

var booking = _context.Bookings.FirstOrDefault(b => b.Id == id 
                                                   && b.Username == fullUsername);

2. 添加异常处理与用户反馈 #

在删除操作中捕获数据库异常，返回友好提示：

[HttpPost]
public IActionResult ConfirmCancelBooking(int id)
{
    string fullUsername = User.Identity.Name; 
    var booking = _context.Bookings.FirstOrDefault(b => b.Id == id 
                                                       && b.Username == fullUsername);

    if (booking == null)
    {
        return NotFound("预订不存在或您无权限删除");
    }

    try
    {
        _context.Bookings.Remove(booking);
        _context.SaveChanges();
        TempData["SuccessMsg"] = "预订已成功取消";
        return RedirectToAction("Index");
    }
    catch (Exception ex)
    {
        TempData["ErrorMsg"] = $"取消失败：{ex.Message}";
        return View("CancelBooking", booking);
    }
}

3. 视图添加状态提示 #

在视图中增加成功/错误消息显示：

@{
    ViewBag.Title = "Cancel Booking";
}

@if (TempData["SuccessMsg"] != null)
{
    <div class="alert alert-success">@TempData["SuccessMsg"]</div>
}
@if (TempData["ErrorMsg"] != null)
{
    <div class="alert alert-danger">@TempData["ErrorMsg"]</div>
}

<h2>Cancel Booking</h2>

<p>Are you sure you want to cancel your booking for @Model.SelectedDate?</p>

@using (Html.BeginForm("ConfirmCancelBooking", "Booking", FormMethod.Post))
{
    @Html.HiddenFor(model => model.Id)
    <input type="submit" value="Confirm Cancellation" class="btn btn-danger" />
    <a href="@Url.Action("Index", "Booking")" class="btn btn-secondary">Back to Bookings</a>
}

内容的提问来源于stack exchange，提问作者Josh