无法从控制器访问viewdata和viewbag来查看 [英] can't access viewdata and viewbag from controller to view

问题描述

嗨朋友



i无法通过viewdata或viewbag从控制器发送数据查看。

请帮我解决这个问题。

这是我的代码：

   控制器 
 
 public ActionResult BookCourse（string Id）
 {
 services（）; 
 var item = _courseDetailsS​​ervice.GetAll（）; 
 ViewBag.Code = Id.ToString（）; 
 ViewBag.Course = item; 
 TempData [code] = Id; 
 ViewBag.title =预订课程; 
 ViewBag.Flag = false; 
 return View（）; 
} 
 [HttpPost] 
 
 [RecaptchaControlMvc.CaptchaValidator] 
 public ActionResult BookCourse（CourseBooking book，bool captchaValid，string captchaErrorMessage）
 {
尝试
 {
 services（）; 
 string code = TempData [code]。ToString（）; 
 bool valid = true; 
 
 if（！captchaValid）
 {
 ViewBag.ErrorMessage =Invalid Entry *; 
 ModelState.AddModelError（Captcha，请正确输入验证文本）; 
有效= false; 
} 
 
 if（book.FirstName == null || book.FirstName ==）
 {
 ModelState.AddModelError（FirstName，Enter名字）; 
有效= false; 
} 
 if（book.LastName == null || book.LastName ==）
 {
 ModelState.AddModelError（LastName，输入姓氏） ; 
有效= false; 
} 
 
 
 if（book.EmailAddress == null || book.EmailAddress ==）
 {
 ModelState.AddModelError（EmailAddress ， 输入电邮地址）; 
有效= false; 
} 
其他
 {
 string emailRegex = @^（[a-zA-Z0-9_ \-\。] +）@（（\ [[ 0-9] {1,3}+ 
 @\。[0-9] {1,3} \。[0-9] {1,3} \。）|（（ [a-zA-Z0-9 \  - ] + \+ 
 @。）+））（[a-zA-Z] {2,4} | [0-9] {1， 3}）（\]）$？; 
 Regex re = new Regex（emailRegex）; 
 if（！re.IsMatch（book.EmailAddress））
 {
 ModelState.AddModelError（Email，Email Address is invalid）; 
有效= false; 
} 
} 
 if（！valid）
 {
  ViewBag.Flag = true; 
返回BookCourse（代码）;  
} 
 book.DateBooked = DateTime.Now; 
 _courseBookingService.Add（book）; 
 SendNotificationMail（书籍）; 
} 
 catch（Exception ex）
 {
 _log.Log（ex）; 
} 
返回RedirectToAction（谢谢）; 
} 
  查看（图书课程）  
 @if（（bool）ViewBag.Flag）
 {
< div id =note> 
< div class =notification_error> 
 @ Html.ValidationSummary（false）
< / div> 
< / div><！ - 结束通知 - > 
} 

这个我不能在视图book course中使用viewbag.flag

解决方案

;
Regex re = new Regex（emailRegex）;
if（！re.IsMatch（book.EmailAddress））
{
ModelState.AddModelError（电子邮件，电子邮件地址无效）;
有效= false;
}
}
if（！valid）
{
ViewBag.Flag = true;
返回BookCourse（代码）;
}
book.DateBooked = DateTime.Now;
_courseBookingService。添加（书籍）;
SendNotificationMail（书籍）;
}
catch（例外） ex）
{
_log.Log（ex）;
}
返回RedirectToAction（谢谢）;
}
查看（图书课程）
@if（（bool）ViewBag.Flag）
{
< div id =note>
< div class =notification_error>
@ Html.ValidationSummary（false）
< / div>
< / div><！ - 结束通知 - >
}

这个我不能在视图book course中使用viewbag.flag

您放入ViewBag / ViewData的数据仅在您填充它的请求的生命周期内可用。 MVC没有回发帖。如果你需要一些东西来坚持多个请求，你应该使用Session。

1. ViewBag 是一个用于缓存的缓存将数据保存在控制器中并在视图中使用它们，它的值在回发之间丢失。



2.所以你必须设置值 ViewBag.Flag 对于控制器中的所有可能情况，不仅对于某些 if 分支，例如您可以在开始时设置默认值值<！/ BLOCKQUOTE>

Hi friends

i can't send data through the viewdata or viewbag from controller to view.
please help me to resolve this.
here is my code:

Controller

public ActionResult BookCourse(string Id)
        {
            services();
            var item = _courseDetailsService.GetAll();
            ViewBag.Code = Id.ToString();
            ViewBag.Course = item;
            TempData["code"] = Id;
            ViewBag.title = "Booking Course";
            ViewBag.Flag = false;
            return View();
        }
        [HttpPost]

        [RecaptchaControlMvc.CaptchaValidator]
        public ActionResult BookCourse(CourseBooking book, bool captchaValid, string captchaErrorMessage)
        {
            try
            {
                services();
                string code = TempData["code"].ToString();
                    bool valid = true;
                
                    if (!captchaValid)
                    {
                        ViewBag.ErrorMessage = "Invalid Entry *";
                        ModelState.AddModelError("Captcha", "Please Enter verification text correctly");
                        valid = false;
                    }

                    if (book.FirstName == null || book.FirstName == "")
                    {
                        ModelState.AddModelError("FirstName", "Enter First Name");
                        valid = false;
                    }
                    if (book.LastName == null || book.LastName == "")
                    {
                        ModelState.AddModelError("LastName", "Enter Last Name");
                        valid = false;
                    }


                    if (book.EmailAddress == null || book.EmailAddress == "")
                    {
                        ModelState.AddModelError("EmailAddress", "Enter Email Address");
                        valid = false;
                    }
                    else
                    {
                        string emailRegex = @"^([a-zA-Z0-9_\-\.]+)@((\[[0-9]{1,3}" +
                                                 @"\.[0-9]{1,3}\.[0-9]{1,3}\.)|(([a-zA-Z0-9\-]+\" +
                                                    @".)+))([a-zA-Z]{2,4}|[0-9]{1,3})(\]?)$";
                        Regex re = new Regex(emailRegex);
                        if (!re.IsMatch(book.EmailAddress))
                        {
                            ModelState.AddModelError("Email", "Email Address is not valid");
                            valid = false;
                        }
                    }
                    if (!valid)
                    {
                        ViewBag.Flag = true;                        
                        return BookCourse(code);
                    }
                    book.DateBooked = DateTime.Now;                
                    _courseBookingService.Add(book);
                    SendNotificationMail(book);                   
            }
            catch(Exception ex)
            {
                _log.Log(ex);
            }            
                return RedirectToAction("Thanks");           
        }
View(Book Course)
 @if ((bool)ViewBag.Flag)
        {
             <div id="note">
                <div class="notification_error">
                    @Html.ValidationSummary(false)
                </div>
            </div><!-- End notification -->
        }

in this i can't use viewbag.flag in view "book course"

解决方案

"; Regex re = new Regex(emailRegex); if (!re.IsMatch(book.EmailAddress)) { ModelState.AddModelError("Email", "Email Address is not valid"); valid = false; } } if (!valid) { ViewBag.Flag = true; return BookCourse(code); } book.DateBooked = DateTime.Now; _courseBookingService.Add(book); SendNotificationMail(book); } catch(Exception ex) { _log.Log(ex); } return RedirectToAction("Thanks"); } View(Book Course) @if ((bool)ViewBag.Flag) { <div id="note"> <div class="notification_error"> @Html.ValidationSummary(false) </div> </div><!-- End notification --> }

in this i can't use viewbag.flag in view "book course"

The data you put in the ViewBag/ViewData is only available during the life-cycle of the request within which you populated it. MVC does not have post backs. If you need something to persist over more than a single request, you should use Session.

1.ViewBag is a cache used to save data in the controller and use them in the view, and its value is lost between postbacks.

2.So you have to set the value "ViewBag.Flag" for all possible cases in your controller, not only for some if branches, for example you could set at beginning a default value!

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