While Ive seen plenty of examples in PHP, can't seem to find one in VB, I want to know if this is even possible.
I have a page, a session starts on page load (using global.asax) the user may not move from (or interact with) that page for a long while and I dont want to increase the session timeout. When the session times out after say.. 20 minutes, I want to start a new one, without moving from the page.
I also don't want constant keep-alives
I want to do it via another method (timer, button press...)
Is this even possible?
If you want to extend the session without a constant keep-alive, and prefer the user to click a button, or base it on a timer, then I would advise that you use fire an AJAX request to the server and not expect any type of a response. Simply doing so will keep the session alive. You can fire this request on any of your preferred criteria using javascript/jquery.
Related
I've got an asp:TextArea that I would like to do some processing (filtering a list) as the user types. I'm sure I could do the filtering within a javascript function called via the onkeyup event, but I'd prefer to do it in my VB.NET code.
Is it possible to do such a thing, or should I just stick with the Javascript? If the latter, could you please explain why?
Thanks!
Stick to the javascript, for one simple reason: postback will lag.
Think about how fast you type. And think about how fast your server responds when a postback is submitted. Now, what will happen when the user types "Hello, world!" in two seconds? He'll get to "Hell" and then the browser will load the postback response. And the user will be back at "H". If every time your user tries to type something you delete a couple of letters, he'll hate your interface.
Doing it with javascript isn't harder than doing it with VB.Net - use jQuery or some other javascript library that makes your life easy, and you'll be filtering that list without keeping your users waiting.
I'd stick with Javascript. otherwise you are going to be posting back to the server each time the user enters a letter which is going to be slow and awkward from a usability perspective.
Depends on the number of possible Users.
Imagine that plenty of users are entering text simultaneously. This would overstress your Server bandwith/RAM/CPU. But if thats not an issue you could use Ajax and make an Async Postback on the Textbox' client event OnChange.
I'm developing an application using ASP.Net.
For first the idea: "My WebApp needs an chronometerto be shared by users and all users will se the same value in cronometer. When a user clicks on a button, the cronometer needs to be restarted and all users will need to see that!"
All right, now I'd like to know what's the best choose to improve more performace an make sure that all users will see the same value in chronometer?
Need I use JSon (with jquery in client side), Timer with UpdatePanel of Ajax Extensions, pure Ajax (with JQuery) or any idea to suggested ? Any suggestion for how to shared a cronometer for all users in C# (put information in Cache or database) ?
Thanks all
Cheers
It is impossible for all users to see the same value in the chronometer. JQuery will be faster than an UpdatePanel (an UpdatePanel needs to post the whole page back to the server), but still some kind of polling to the server is needed. You could set the polling period to 1 second - in that case the difference in users' chronometers will be at the most 1 second. Even that value however is too low for a repeating Ajax request and could easily hog browser's resources.
I am trying to come up with a way to measure how long a user has been on a page in my ASP.NET application. I am storing the userid, pagename, pageenteredtime and pagelefttime in a database. Each record has its own unique id as well, called featureuselogid.
At the moment, I can track when a user comes into the page with the page_load function on the server side. I store the userid, pagename and pageenteredtime.
After that im stuck, and need some guidance in the right direction. I need to record the time the user leaves the page. I know in javascript there is a window.onbeforeunload function, which will cover most cases (browser shutdown, links etc).
But how do I pass the featureuselogid to the javascript? If i can do that, I think I can make a webservice call from the javascript and update the record with the pagelefttime.
Am I going down the wrong path?
Cheers in advance.
You will have to run Javascript timer on the client that periodically calls the server. Once the call does not get logged at the expected time, it means that the user has left. Woopra does this, and it works reliably. For instance, sometimes people have a page loaded in a browser in the background for days, and there is no other way of detecting that they are still connected.
Users on laptops pulling the network cable, moving out of the coverage of a Wifi zone, etc etc there are too many scenarios where the onbeforeunload event will not reach a server anymore.
Just put the featureuselogid in a hidden field in the page, with a unique ID that will make it accessible to Javascript, or set a javascript variable.
Having said that, I believe that you are going to be able to most reliably detect Page_Load. You can determine the time between pages by measuring the time between Page_Load events. You won't get the browser closure, but IMO knowing when the user closes the browser is not all that meaningful.
When you render the page in ASP.net, include a javascript tag that assigns a variable to the value of a server side script:
<script language="javascript">
var JS_featureuselogid = <%= featureuselogid %>;
</script>
Later in your javascript code, you can reference the JS_featureuselogid variable and get the value that was injected into it during page construction.
I work on ASP.NET C#. Under button click event I want to save something it's work fine, but after press the refresh button of browser, this event occurs again I want to stop this event.
An article on this subject.
Preventing Duplicate Record Insertion on Page Refresh
Approach 1
A simple solution is to
Response.Redirect back to the same
page after the INSERT command is
called. This will call up the page
without transmitting any post headers
to it. Using Request.Url.ToString()
as the first parameter of
Response.Redirect will cause both the
URL and the page's querystring to be
included in the redirect. The use of
false as the second parameter will
suppress the automatic Response.End
that may otherwise generate a
ThreadAbortedException. A
disadvantage of this approach is that
any ViewState that had been built up
will be lost.
Approach 2
A related approach would be for the form to submit to an intermediate processing page and then Response.Redirect back to the calling page, similar to the classic ASP approach to form processing. This has the same effect as simply using the Response.Redirect in the Button_Click event so it has the same disadvantages, with the added disadvantage of creating another page for the website developer to manage.
Approach 3
The next batch of solutions works by
determining whether the user has
refreshed the page in the browser
instead of pressing the form's submit
button. All of these solutions depend
on the ability of the website to use
Session variables successfully. If
the website uses cookie-based
Sessions, but the user's browser does
not permit the use of cookies, these
solutions would all fail.
Additionally, should the Session
expire these solutions would also
fail.
Approach 4
Should the user somehow manage to
circumvent the above mentioned solutions described
above, the last line of defense is at
the database. There are two methods
that can be employed to prevent a
duplicate record from being inserted
into the database. For each method,
I've moved the SQL code into a stored
procedure, since there are now more
processing steps involved and these
are easier to illustrate in a separate
stored procedure. Note however that a
stored procedure is not strictly
required in order for these methods to
work.
I am using VS 2005, C# 2, ASP.Net 2.0
I am unable to find out how to track that user pressed F5/Ctrl+F5/ Open a new Window(Ctrl + N) in ASP.Net.
I know that there is a Page.IsPostBack property, which tells that a page is loaded in response to an action taken by user.
I am just curious to know, that why isn't there a property as IsRefresh or Page.IsRefresh in ASP.Net, which will return true,
whenever user takes any of the above actions.
Is there a way to know this?
Actually my problem is that i have a DLL using which all of my aspx pages are inherited, I have to
insert some values in a table whenever the page is opened for the first time that's it, if user just opens the page or do not take any action,
an entry should be inserted into the database, but as far as I have tried, I controlled it anyhow using the Page.IsPostBack property, but I got stuck
in the refresh case, as it is inserting records unconditionally.
Similar to using a function in Global.asax (as others have suggested) you could use a session variable "flag". When the page first loads set a session variable and then just check against it in your page load function:
if (Session("visited") != "true"
//page has not been visited, log visit to DB
Just make sure you set the session flag sometime after the above check during the page load.
It won't be exact (sessions can timeout while a page is active, users can completely leave the site and come back in the same browser and the session stays alive, etc) but for your tracking it is much better than counting every page hit in the DB.
Perhaps you want the Session_Start method in the Global.asax file, which will be triggered once at the start of each user session?
In your Global.asax file, add or edit the method:
void Session_Start(object sender, EventArgs e)
{
}
why isn't there a property as IsRefresh or Page.IsRefresh in ASP.Net
Because ASP.NET cannot possibly know. The browser does not send any information that could allow it to determine whether the page is being requested due to a refresh or normal load. You will need to reconsider your requirements: what is the actual purpose of the database logging?
Session_Start method in Global.asax file is fired every time when a browser session is started. You can use this method to count number of unique users on your website.
Session_End method in Global.asax is fired when a session ends (explicitly or timedout). So you can decrement the count here.
Hope the above to example uses of these methods helps you understand how you can use them.
Because of the stateless nature of HTTP protocol there is no way to tell apart the initial load from the refresh
As has already been said. This isn't possible. A request issued due to a refresh is no different to a request issued the first time the page is loaded.
It sounds to me like you are trying to track page views somehow. This is certainly possible though it will require some work on your part. Your best bet is probably to log the URL of the page. You may also want to include the query string in order to differentiate between page loads for different pieces of data (if this happens in your application). You will also want to log the ID of the current user, and the ID of their session.
You can then make sure that you don't insert two page views for the same user for the same page in the same session, effectively filtering out any reloads of a page.
You do need to be aware that this isn't the same as detecting a refresh, what you are detecting is two page views in the same session, this could be a refresh, or it could be use of the back button, or just reloading from the address bar.
My suggestion would be to create a cookie on very first load, then on Page_Load check to see if the cookie exists. If it does, don't insert the record. You can use Session_End to destroy or create the cookie as someone suggested if that works with your application's architecture.