How to remember viewstate after redirecting? - viewstate

Main page has a gridview with options to filter / search etc...
when a user selects a row a NEW page comes up (response.redirect) and i can edit/insert/delete there...
I want the user to be able to go back to the page he came (easy) BUT i want the grid to have the filters as they where on the time of the first redirect.
anything ready in .net or i have to use lets say querystring back and forth to do it?

Avoid using Response.Redirect
Instead of using Response.Redirect, use Server.Transfer where ever you can. Response.Redirect sends response to the client which then sends a new request to the server. Server.Transfer however performs the redirect on the server. Only use Response.Redirect when you want authentication and authorization to be performed on redirects or you want URL on client browser to be changed because Server.Transfer will not do this as it is a server side transfer.
This way you'll be able to preserve the prvious page folrms collections..
look here:
http://www.codeproject.com/Tips/74472/ViewState-and-Server-Transfer-Best-practices
and also "Passing Server Control Values Between Pages" :
http://msdn.microsoft.com/en-us/library/6c3yckfw(vs.71).aspx

Request.UrlReferrer will return the previous URL request. Use hidden controls to retain the value if you use MVC

Related

Detect when user navigate from one web page to another

I am writing MVC3 web app I need to know at server side when user navigate from one web page to another. I do not need to know from what pages page to which just fact that user navigated. I could find this by adding Session variable to every Home Controller Actions but maybe there is better solution?
Use a global filter attribute for al your controller actions. You can set that attribute in the global asax. In that case you know when an action is hit.
You could try sending AJAX request bound to onbeforeunload browser event.
Basically, it happens on the client side, so the programming should also be in client. Javascript could be the way to go. Though it may deliver some inconvenience to the user.

What are my options for changing the querystring on a URL, and updating browser history?

Is there any way I can change the URL or add more history to the "back button" without having to refresh the entire page?
My application is AJAX based and I'd like to add some "undo" events to history so that the user can simply hit back and retain the old values.
What's possible today? I hear some of this may be in HTML5 but haven't checked whats supported in current browsers.
I think you can use window.location.hash to track the #part of the page, in your case, #state1, #state2 and so on.
window.location.hash = '#state' + (++ stateN) to set and
stateN = parseInt(window.location.hash.match(/\d+$/)[0])
See On - window.location.hash - Change? for more details about how to detect location hash changes.
You could use 301 redirection. Personally, I would use cookies on the client side, or sessions in your back end, to store the breadcrumbs. Storing state information in the URL is a bad idea for AJAX applications, because people might return to a url that the server side is not in the right state to respond to.
Another option would be to provide your own Back button that knows which page to go back to.
The answer for this question will be more or less the same as my answers for these questions:
How to show Ajax requests in URL?
How does Gmail handle back/forward in rich JavaScript?
In summary, two projects that you'll probably want to look at which explain the whole hashchange process and using it with ajax are:
jQuery History (using hashes to manage your pages state and bind to changes to update your page).
jQuery Ajaxy (ajax extension for jQuery History, to allow for complete ajax websites while being completely unobtrusive and gracefully degradable).
It is possible to use ASP.NET's built in Script Manager to update the browser's history. A full how-to to do this is located here:
http://www.asp.net/aspnet-in-net-35-sp1/videos/introduction-to-aspnet-ajax-history

Cache web forms in client side

is it possible to cache form contents on client side? Like maintaining state even if the form is un-saved and the user moves to a new page then returns back to the form?
The best way to do this would be by using Javascript/AJAX to talk to the server, saving each form field as the user went off it. Then, when you load the page, you'd see if there was any content for each form already saved.

How do you convert a form with method="get" to a mod_rewrite url?

I have a PHP MVC Web App and Apache mod_rewrite rules already working fine, but when I create forms using method="get", the submitted URL looks like
contact/submit?a=b&c=d
I would like my form to submit to
contact/submit/a/b/c/d
Both posting and getting the form work fine on the server side, but when using post method, the back button always asks for reposting the form values and furthermore I want the strings in the URL for SEO. I think JQuery might let me intercept the form submit event and refresh to the url dynamically, but it it seems there must be an easier way to do it that I am missing.
You could use the POST->REDIRECT->GET pattern that Spring Web Flow utilizes. This would allow you to post as you wish and then redirect to contact/submit/a/b/c/d. It would also solve the problem with the back button asking you if you want to resubmit your form data. See this related article.
The GET method uses standard query string arguments to pass form data via an HTTP GET request.
The HTTP GET request is not intended to modify any data on the server. POST is designed for modifying data on the server.
GET may be cached. POST will not.
/a/b/c/d is not a standard format (as in RFC) for passing data. However, for requesting data or URLs to post to, that has become popular.
So, if you are updating server data, just use a POST -> REDIRECT -> /a/b/c/d.
If you are just reading data from the server, then you will need to use a bit of Javascript to read your form values and construct a query string, and then go to it with window.location = ...
Have fun!

Firefox 3 doesn't allow 'Back' to a form if the form result in a redirect last time

Greetings,
Here's the problem I'm having. I have a page which redirects directly to another page the first time it is visited. If the user clicks 'back', though, the page behaves differently and instead displays content (tracking session IDs to make sure this is the second time the page has been loaded). To do this, I tell the user's browser to disable caching for the relevant page.
This works well in IE7, but Firefox 3 won't let me click 'back' to a page that resulted in a redirect. I assume it does this to prevent the typical back-->redirect again loop that frustrates so many users. Any ideas for how I may override this behavior?
Alexey
EDIT: The page which we redirect to is an external site over which we have no control. Server-side redirects won't work because this wouldn't generate a 'back' button for in the browser.
To quote:
Some people in the thread are talking about server-side redirect, and redirect headers (same thing)... keep in mind that we need client-side redirection which can be done in two ways:
a) A META header - Not recommended, and has some problems
b) Javascript, which can be done in at least three ways ("location", "location.href" and "location.replace()")
The server side redirect won't and shouldn't activate the back button, and can't display the typical "You'll be redirected now" page... so it's no good (it's what we're doing at the moment, actually.. where you're immediately redirected to the "lucky" page).
I think the Mozilla team takes a step into the right direction by breaking this particularly annoying pattern. Finding a way around it somehow defies the purpose, doesn't it?
Instead of redirecting on first encounter, you could simply make your page render differently when a user hits it the first time. Should be easy enough on the server side, since you already have the code that is able to make that distinction.
You can get around this by creating an iframe and saving the state of the page in a form field in the iframe before doing the redirect. All browsers save the form fields of an iframe.
This page has a really good description of how to get it working. This is the same technique google maps uses when you click on map search results.
I'm strongly in favor for the Firefox behaviour.
The most basic way to redirect is to let the server send HTTP status code 302 + Location header back to the client. This way the client (typically a browser) will not place the request URI into its history, but just resend the same request to the advocated URI.
Now it seems that Firefox started to apply the bevaviour also for server responses that try redirections e.g. by Javascript's onload event.
If you want the browser not to display a page, I think the best solution is if the server does not send the page in the first place.
Its possibly in aide to eliminate repeated actions.
A lot of ways people do things is
page 1 -> [Action] -> page 2 -> redirect to page 2 without the action parameters.
Now if you were permitted to click the back button in this situation and visit the page without the redirect, the action would be blindly re-performed.
Instead, firefox presumes the server sent a redirect header for a good reason.
Although it is noted, that you can however have content delivered after the redirect header, sending a redirect header ( at least in php ) doesn't terminate execution, so in theory, if you were to ingnore the redirect request you would get the page doing weird stuff.
( I circumvent this by the fact all our redirects are done via the same function call, where i call an explicit terminate directly after the redirect, because people when coding assume this is how it behaves )
In the URL window of firefox type about:config
Change this setting in firefox
browser.sessionstore.postdata
Change from a 0 to 1

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