查看未找到 - asp.net mvc 错误

Question

我收到一条错误消息，提示尚未找到视图更新，我想显示 TaskDetail 视图而不是更新视图...

    [HttpPost]
    [ValidateAntiForgeryToken]
    public ActionResult Update(int taskid, string status)
    {
        if (!status.Equals("closed", StringComparison.OrdinalIgnoreCase) &&
            !status.Equals("opened", StringComparison.OrdinalIgnoreCase))
            ModelState.AddModelError("", "incorrect status, please try again");

        if (!this.ModelState.IsValid)
            return TaskDetail(taskid);

        if (status.Equals("Closed", StringComparison.OrdinalIgnoreCase))
            _service.CloseTask( taskid, true);
        else
            _service.CloseTask(taskid, false);

        this.FlashInfo("success, task status has been updated...");
        return RedirectToAction("TaskDetail");

}

例外：

$exception{"The view 'Update' or its master was not found. The following locations were searched:\r\n~/Areas/Tasks/Views/TaskManager/Update.aspx\r\n~/Areas/Tasks/Views/TaskManager/Update.ascx\r\n~/Areas/Tasks/Views/Shared/Update.aspx\r\n~/Areas/Tasks/Views/Shared/Update.ascx\r\n~/Views/TaskManager/Update.aspx\r\n~/Views/TaskManager/Update.ascx\r\n~/Views/Shared/Update.aspx\r\n~/Views/Shared/Update.ascx"} System.Exception {System.InvalidOperationException}

任务详情：（这是在同一个控制器内）

    [HttpGet]
    public ActionResult TaskDetail(int taskid)
    {
        var loggedonuser = _repo.GetCurrentUser();


        var companies = _repo.All<Company>();
        var users = _repo.All<User>();

        var task = _repo.Single<InstructionTask>
            (x => x.TaskID == taskid && (x.CompanyID == loggedonuser.CompanyID || x.AssignedTo.Contains(loggedonuser.CompanyType.ToString())));

        var dto = new TaskDTO
        {
            TaskID = task.TaskID,
            Title = task.Title,
            Description = task.Description,
            DateCreated = task.DateCreated,
            IsClosed = task.IsClosed,
            CompanyID = companies.Where(y => task.CompanyID == y.CompanyID).SingleOrDefault().Identifier,
        };

        var checkedtags = TaskTagsHelper.GetTags(task.AssignedTo);

        var t = TaskTagsHelper.GetPanelTags();

        if (checkedtags != null) //if tags are present only then tick them off...
        {
            foreach (var item in t.Keys.ToList())
            {
                if (checkedtags.Any(x => x == item))
                    t[item] = true;
            }
        }

        dto.AvailableTags = t;

        if (task.DueDate.HasValue)
            dto.DueDate = task.DueDate.Value;

        var comments = _repo.All<TaskComment>()
            .Where(x => x.TaskID == task.TaskID)
            .OrderByDescending(x => x.Timestamp)
            .Select(x => new TaskCommentDTO
            {
                Comment = x.Comment,
                Timestamp = x.Timestamp,
                CompanyID = companies.Where(y => x.CompanyID == y.CompanyID).SingleOrDefault().Identifier,
                UserID = users.Where(y => x.UserID == y.UserID).SingleOrDefault().Login,
                Type = EnumHelper.Convert<TaskCommentType>(x.Type)
            });

        dto.AllComments = comments;

        return View(new TaskViewModel
        {
            TaskDetail = dto,
            NewComment = new TaskCommentDTO()
        });
    }

我在我的基本控制器中发现了异常：

    //Generic methods/ controllers/ attributes will be applied here...
    protected override void OnException(ExceptionContext filterContext)
    {
        //dont interfere if the exception is already handled
        if (filterContext.ExceptionHandled)
            return;

        //let the next request know what went wrong
        filterContext.Controller.TempData["exception"] = filterContext.Exception;

        //logg exception

        //set up redirect to my global error handler
        filterContext.Result = new ViewResult { ViewName = "~/Views/Error/PublicError.aspx" };

        //advise subsequent exception filters not to interfere and stop
        // asp.net from showing yellow screen of death
        filterContext.ExceptionHandled = true;

        //erase any output already generated
        filterContext.HttpContext.Response.Clear();
    }

Answer 1

根据我对您代码的理解，您正在从 Update 方法调用 TaskDetail 操作。不建议这样做。原因如下：

1. 请求的所属上下文是 Update 方法，这就是它尝试呈现“Update”视图的原因。这是因为按照惯例，视图是根据被击中的第一个动作来选择的。 MVC 不知道您调用了 TaskDetail。
2. 这违反了 PRG 模式 (Post-Redirect-Get)。我建议您在此处阅读此内容：http://en.wikipedia.org/wiki/Post/Redirect/Get - 基本上，您真的不应该从 HTTP POST 中呈现任何内容。您应该重定向回 GET。不这样做会导致各种问题。

如果您希望它按原样工作，您可以通过将 TaskDetail 的最后一行更改为以下内容来做到这一点，以便它知道始终呈现 TaskDetail 视图，但我不建议这样做：

return View("TaskDetail", ...viewModel...)

Answer 2

那么显而易见的问题是：

您在以下文件夹之一中有文件吗：

Views\ControllerName\TaskDetail.aspx
Views\ControllerName\TaskDetail.ascx
Views\Shared\TaskDetail.aspx
Views\Shared\TaskDetail.ascx

其中 ControllerName 是您的 Update 方法所在的控制器的名称。也就是说，如果您的控制器是 HomeController，那么您的文件夹就是 \Views\Home\

编辑：
我对您的 ModelState.IsValid 调用也有些困惑，但主要是因为您没有包含 TaskDetail 控制器操作。如果您的模型状态无效，您是否不想返回更新视图以便用户可以更正错误并重新提交？还是他们从 TaskDetail POST 到 Update 操作？