C# ASP.NET MVC：返回重定向和 ViewData
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ASP.NET MVC: return Redirect and ViewData
提问by pistacchio
I have a login box in my MasterPage. Whenever the login information is not correct, I valorize ViewData["loginError"]to show the error message to the user.
我的 MasterPage 中有一个登录框。每当登录信息不正确时，我都会ViewData["loginError"]向用户显示错误消息。
Login is an action of the UserController, so the form that contains the login has action = "/User/Login".
登录是 UserController 的一个动作，所以包含登录的表单有action = "/User/Login".
As a user can try to log in from any page, in case of success I redirect him to his personal page, but in case of error I want him to stay on the very same page where he tried to login. I've found that this works:
由于用户可以尝试从任何页面登录，如果成功，我会将他重定向到他的个人页面，但如果出现错误，我希望他停留在他尝试登录的同一页面上。我发现这有效：
return Redirect(Request.UrlReferrer.ToString());
but it seems that, as I'm not returning a proper view, the data on ViewData is lost, so I cannot show the error message.
但似乎，由于我没有返回正确的视图，ViewData 上的数据丢失了，所以我无法显示错误消息。
Any suggestion on how to solve this and similar problems?
关于如何解决这个问题和类似问题的任何建议？
Thanks
谢谢
采纳答案by roryf
You probably want to use the TempDataproperty, this will be persisted across to the next HTTP request.
您可能想要使用该TempData属性，这将持续到下一个 HTTP 请求。
回答by tvanfosson
Why not handle the login via AJAX instead a full post? You could easily supply the status, a redirect URL, and any error messages via JSON.
为什么不通过 AJAX 处理登录而不是完整的帖子？您可以通过 JSON 轻松提供状态、重定向 URL 和任何错误消息。
public ActionResult Logon( string username, string password )
{
...
// Handle master page login
if (Request.IsAjaxRequest())
{
if (success)
{
return Json( new { Status = true, Url = Url.Action( "Index", "Home" ) } );
}
else
{
return Json( new { Status = false, Message = ... } );
}
}
else // handle login page logon or no javascript
{
if (success)
{
return RedirectToAction( "Index", "Home" );
}
else
{
ViewData["error"] = ...
return View("Logon");
}
}
}
Client-side
客户端
$(function() {
$('#loginForm input[type=submit]').click( function() {
$('#loginError').html('');
$.ajax({
url: '<%= Url.Action("Logon","Account") %>',
dataType: 'json',
type: 'post',
data: function() { return $('#loginForm').serialize(); },
success: function(data,status) {
if (data.Status) {
location.href = data.Url;
}
else {
$('#loginError').html( data.Message );
}
}
});
return false;
});
});
回答by xandy
Normally for most web sites, when user fail to authenticate (due to password or so), it will go to another page which help the user with (like password retrieve, or ask the user to sign up) which is rare to stay in the very same page. I think you can re-consider that you really need the navigation that you are using.
通常对于大多数网站来说，当用户无法通过身份验证（由于密码等）时，它会转到另一个帮助用户的页面（例如找回密码，或要求用户注册），这很少会停留在非常相同的页面。我认为你可以重新考虑你真的需要你正在使用的导航。
OK, one solution if you really want to stick to your model, is that you can attach the login error to the URL. For example, http://www.example.com/index.aspx?login_error=1indicates that error occurs, and you can use BEGIN_REQUEST (or HTTP Module) to capture this, and tell the model state about the error:
好的，如果你真的想坚持你的模型，一种解决方案是你可以将登录错误附加到 URL。例如http://www.example.com/index.aspx?login_error=1表示发生了错误，可以使用 BEGIN_REQUEST（或 HTTP Module）来捕获这个，并告诉模型状态关于错误：
ModelState.AddModelError(...);
BTW, add model error is actually a more proper way to inform the view about any error rather than using ViewState (this is similar to throwing exception vs returning an integer about the execution result in old days).
顺便说一句，添加模型错误实际上是一种更恰当的方式来通知视图任何错误，而不是使用 ViewState（这类似于抛出异常与返回有关过去执行结果的整数）。
While using AJAX to login (as suggested by tvanfosson) is perfectly achievable and it sometimes excel in user experience, classic full-post is still inreplacable (consider some user will disable javascript, or even on my dump WM6 handset that doesn't support javascript).
虽然使用 AJAX 登录（如 tvanfosson 建议）完全可以实现，并且有时在用户体验方面表现出色，但经典的全文仍然不可替代（考虑某些用户会禁用 javascript，甚至在我的不支持 javascript 的转储 WM6 手机上）。
回答by Rake36
I'm confused. Doesn't
我糊涂了。没有
return View();
just return the current page back to you?
只是将当前页面返回给您？
So in your case, when login fails, set your viewdata and call return View();
所以在你的情况下，当登录失败时，设置你的 viewdata 并调用 return View();
i.e.
IE
if (!FailedLogin) {
//Go to success page
}else{
//Add error to View Data or use ModelState to add error
return View();
}
Are you using the [Authorize] decorator? The MVC login process auto prompts with the login page and then returns you to the controller action you were trying to execute. Cuts down on a lot of redirecting.
你在使用 [Authorize] 装饰器吗？MVC 登录过程会自动提示登录页面，然后将您返回到您尝试执行的控制器操作。减少了很多重定向。
回答by hunaid mushtaq
The following example would hopefully help you out in resolving this issue:
以下示例有望帮助您解决此问题：
View.aspx
视图.aspx
<%= Html.ValidationSummary("Login was unsuccessful. Please correct the errors and try again.") %>
<% using (Html.BeginForm()) { %>
<div>
<fieldset>
<legend>Account Information</legend>
<p>
<label for="username">Username:</label>
<%= Html.TextBox("username") %>
<%= Html.ValidationMessage("username") %>
</p>
<p>
<label for="password">Password:</label>
<%= Html.Password("password") %>
<%= Html.ValidationMessage("password") %>
</p>
<p>
<%= Html.CheckBox("rememberMe") %> <label class="inline" for="rememberMe">Remember me?</label>
</p>
<p>
<input type="submit" value="Log On" />
</p>
</fieldset>
</div>
<% } %>
AccountController.cs
账户控制器.cs
private bool ValidateLogOn(string userName, string password)
{
if (String.IsNullOrEmpty(userName))
{
ModelState.AddModelError("username", "You must specify a username.");
}
if (String.IsNullOrEmpty(password))
{
ModelState.AddModelError("password", "You must specify a password.");
}
if (!MembershipService.ValidateUser(userName, password))
{
ModelState.AddModelError("_FORM", "The username or password provided is incorrect.");
}
return ModelState.IsValid;
}
You won't be able capture the information added in ViewData after Redirect action. so the right approach is to return the same View() and use ModelState for errors as mentioned by "xandy" as well.
重定向操作后，您将无法捕获在 ViewData 中添加的信息。所以正确的方法是返回相同的 View() 并使用 ModelState 来处理“xandy”提到的错误。
Hope this would give u a head start with form validation.
希望这会让你在表单验证方面领先一步。
