使用 ASP.NET CORE 2 Razor 页面的处理程序错误

Question

我正在尝试在我的 ASP.NET Core 2 Razor 应用程序中使用处理程序函数，在我的模型中我有这个方法：

public async Task<IActionResult> OnPostAddBookingAsync(int? id)
    {
        LoadAvailableRooms();

        TemporaryBookingTable tbt = new TemporaryBookingTable();

        var TemporaryBookingList = from c in _context.TemporaryBookingTables
                                   select c;

        if (!_context.TemporaryBookingTables.Any(t => t.RoomID == id))
        {
            tbt.CustomerID = 0;
            tbt.RoomID = Convert.ToInt16(id);
            tbt.UserID = 0;
            _context.TemporaryBookingTables.Add(tbt);
            await _context.SaveChangesAsync();
        }

        foreach (var item in TemporaryBookingList)
        {
            SelectedRoom = await _context.Rooms.FirstOrDefaultAsync(r => r.RoomID == item.RoomID);
            Room.Add(SelectedRoom);
        }

        return Page();
    }

我正在尝试做的是......在我的 html razor 页面中，我有一个列表，每个项目都有一个用于删除所选项目的按钮。

剃刀页面：

@{
    foreach (var item in Model.Room)
    {
<div>
    <h3>@Html.DisplayFor(modelItem => item.RoomType)</h3>
    <h4>@Html.DisplayFor(modelItem => item.RoomPrice)</h4>
    <form method="post">
        <input type="hidden" />
        <button type="submit" asp-page-handler="DeleteBooking" asp-route-id="@item.RoomID" class="btn btn-default btn-sm">Eliminar</button>
    </form>

</div>
    }

}

当我尝试使用 url 访问此页面时： http://localhost:62755/admin/Booking

我收到此错误：

NullReferenceException: Object reference not set to an instance of an object.
SomethingNewDemo.Pages.admin.Booking_Page+<>c__DisplayClass17_1+<<ExecuteAsync>b__3>d.MoveNext() in Booking.cshtml
+
            <button type="submit" asp-page-handler="DeleteBooking" asp-route-id="@item.RoomID" class="btn btn-default btn-sm">Eliminar</button>
System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
Microsoft.AspNetCore.Razor.Runtime.TagHelpers.TagHelperExecutionContext+<GetChildContentAsync>d__31.MoveNext()
System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
System.Runtime.CompilerServices.TaskAwaiter.GetResult()
Microsoft.AspNetCore.Mvc.TagHelpers.RenderAtEndOfFormTagHelper+<ProcessAsync>d__7.MoveNext()
System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
Microsoft.AspNetCore.Razor.Runtime.TagHelpers.TagHelperRunner+<RunAsync>d__0.MoveNext()
System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
SomethingNewDemo.Pages.admin.Booking_Page+<ExecuteAsync>d__17.MoveNext() in Booking.cshtml
+
        <h4>@Html.DisplayFor(modelItem => item.RoomPrice)</h4>

感谢阅读，你有遇到过这样的问题吗？

Answer 1

您需要在视图操作结果中将模型作为参数传递，否则模型数据不会发送到视图，您将获得账单参考。将控制器操作的最后一行更改为以下内容：

//假设TemporaryBookingTable就是你要显示的 返回页面(TemporaryBookingTable);