I have a situation that I am stuck with, and hoping someone can help. I am building a .NET/C# web application in which I have a tabbed panel layout, and when the user clicks on each of the tabs the display panel is updated using javascript to hide and show some divs. None of these clicks cause postback, it is all client-side, so I can't use viewstate or session.
What I want to do is somehow remember which panel was last visible when the page is refreshed, yet without posting back to the server I am unsure how to do this. I have tried a hidden field but obviously its value is reset every time because the form is never submitted. I do know that I can achieve this using cookies but its a little annoying to implement for such a (seemingly) trivial operation ... but maybe this is the only way?
Does anyone have any more elegant solution to this problem?
Using a function like this to show and hide tabs):
function makeCurrent(tab) {
if (tab.title == 'Manage orders') {
document.getElementById('panelOrders').style.display = "block";
// Hide others
document.getElementById('panelAccounts').style.display = "none";
document.getElementById('panelProducts').style.display = "none";
document.getElementById('panelSettings').style.display = "none";
// Remember last viewed panel
document.getElementById('hdnCurrentlyViewing').value = "orders";
}
The panels are just divs with style.display controlling their visibility. Not sure if its useful to post HTML code because its fairly self explanatory ...?
You can make this happen without a postback is to make an AJAX call from Javascript where you tell your server what the current panel is as you switch it.
I prefer using a framework like JQuery or Prototype to help make these AJAX calls myself.
I think Hidden field will be the best option. have you tried ASP:HiddenField? It can be accessed across postbacks.
But if you still have some reservations with postbacks and hiddenfield you can also use cookies from JS http://techpatterns.com/downloads/javascript_cookies.php this is helper lib for cookies manipulation within JS.
Regards.
Related
We have a page with Telerik RadEditor on a tab strip. There are scenarios when RadEditor contains a lot of html and when doing a post back in order to switch the tab, all its contents is being post back to the server. This results in gigantic performance loss (there are times when post backs are sending tens of MiB of data).
Is it possible to tweak RadEditor in such a way that it does not send its contents over to server on postbacks? Our code-behind does not rely on RadEditors Content property accessor (does not read its content explicitly), only its mutator (its contents are set from within the control's code-behind).
Is it even possible to do such things with any of Telerik controls and if it is, then how do we achieve such result?
It's worth pointing out that we use relatively old Telerik UI version (2013.2.611.35) and we can't switch to a newer version at the moment.
Thank you in advance.
Consider using the ContentUrl of the PageViews. This will let you load separate pages in iframes, so they will postback independently of the main page. Thus, you can have a standalone page with the editor and standalone pages for your other tabs.
On the possibility to exclude something from the POST request - I don't know of a way to do this, as it is not supposed to happen. The whole point is to transfer the current page state to the server.
Another option you may consider is using AJAX and the PageRequestManager's beingRequest event to try to blank out the editor. I have not tried it and I do not know whether it will actually work out, since so much data may simply be too much for the JS engine to process before the postback begins. Here is a bit of code that illustrates the idea:
var currContent = null;
function BeginRequestHandler(sender, args) {
var editor = $find("<%=RadEditor1.ClientID%>");
currContent = editor.get_html(true);
editor.set_html("");
}
function EndRequestHandler(sender, args) {
var editor = $find("<%=RadEditor1.ClientID%>");
editor.set_html(currContent);
currContent = null;
}
Sys.WebForms.PageRequestManager.getInstance().add_beginRequest(BeginRequestHandler);
Sys.WebForms.PageRequestManager.getInstance().add_endRequest(EndRequestHandler);
I have an application that uses WebBrowser control to navigate from page to page, on some pages I get a leaving popup asking me if that's what I want to do.. this stops the whole further execution until I press "Leave" or "Stay".. How can I disable them?
What I've tried so far were these actions:
a) setting window.onbeforeunload = null;
b) setting alert, confirm, prompt to an empty function
c) settin suppressErrorMessages to true
but even so, I still get the nasty message in the end.
I mostly relied on this answer:
How to update DOM content inside WebBrowser Control in C#?
But so far without a success.
The alerts seem to be jQuery alerts because they have custom texts (instead of OK Cancel, they have Stay Leave)..
Any help hugely appreciated!!
The webbrowser control uses IE internally and IE has a prompt if you've filled out a form asking you if you really want to leave the page (thereby losing the content you've filled out) perhaps that's what you're seeing?
i'm just shooting from the hip here but you could try clearing all inputs before navigating.
I have an ASP.Net form (Page1) where the user enters some data and then clicks the submit button.
As part of Page1, I have some Validators, including a CustomValidator which needs to do its validation back on the server.
When the user clicks the submit button a post is done to Page1 and the validation routine is run on the server and as long as I check Page.IsValid in the button click routine the form knows whether things have passed or not.
When the validation doesn't pass everything properly goes back to Form1 and the error message is displayed.
When the form does pass validation, I want to pass the data that the user entered to a second form (Page2) so that Page2 can be rendered correctly based on the data the user entered on Page1.
Is there a generally accepted way, or best way, to pass the data to Page2? Here are some ways I know about:
Call Page2 with a query string: This won't work as I need the data to not be visible to the user in certain cases.
Use the PostBackUrl on the submit button to go to Page2: As far as I know, this won't work correctly because then the server side validation routines for Page1 won't be run.
Use Session Variables: I don't know of a particular reason why this would be bad.
Use Server.Transfer: I don't really have any experience with this.
I would think that this would be a pretty standard thing to do but I'm having a hard time finding any information on the correct way to do it.
If you don't have a form of secondary storage for this data, using either Session storage or Server.Transfer would work.
You might find Server.Transfer is a little neater as, this way, you'll retain your POST values across the transfer. This will potentially save you a lot of cumbersome code playing around with session state, which, depending on how complex your forms are, could open the way to all kinds of unusual behaviour that you'd have to predict and plan to deal with in advance such as what happens when a user clicks the "back" button or - if you're posting across multiple pages - what happens when a session expires (plus Servy's examples of having multiple tabs open on the same page(s), all sharing the same session). Working with session state can be messy.
Perform your validation on PostBack then, if Page.IsValid, do:
Server.Transfer("/FormPage2.aspx");
Server.Transfer preserves Request.QueryString and Request.Form, so you can pick up your POST values on FormPage2 and do whatever you need with them here - whether it be using them for conditional logic or rendering them out again as hidden fields to join them up with the values from the second page of the form (bear in mind that if you're doing this you'll have to revalidate the hidden inputs at this stage).
http://msdn.microsoft.com/en-us/library/y4k58xk7.aspx
I have used session state for handling complex forms in the past and found myself wishing I'd used Server.Transfer, which I plan to use for all similar endeavours in the future, unless I have a very good reason not to.
You might also consider using a multiview, but in my experience these can be very messy.
Hope this helps.
I think that the easiest solution would be to specify a PreviousPageType directive. It specifies a type that the page should expect to receive and you would do a normal POST to that page.
On the second page of your application, use the following directive:
<%# PreviousPageType VirtualPath="~/FirstPage.aspx" %>
You will be able to access the properties exposed and check for validity by using something like this:
if (PreviousPage != null && PreviousPage.IsValid)
Using the Session object is a standard way to pass information across forms.
#Servy gives a good explaination (in the comments below) on how Server.Transfer can help you in this case.
The other options you stated all have problems, just like you mentioned...
If you want to use Session:
In the postback of Page1 you can set the values:
Session["myVar"] = <Data you want to pass to page2>
In page2 in the OnLoad:
if (Session["myVar"] != null)
{
myVar = Session["MyVar"]
}
You can achieve this with Server.Transfer by adding a property to your page1. In your second page in page_load for example:
Page1 prev = Page.PreviousPage as Page1;
if (prev != null)
{
// access your property here and set up the page
}
Server.Transfer can safely receive a query string without fear of the user seeing it.
Instead of Session use Context.Items.
Context.Items["validationProblems"] = "...";
Server.Transfer("FixProblems.aspx");
My other comment is that in my experience it's more "standard" to keep the validation UI contained in the same form that's collecting the information. This enables "real time" feedback. In practice I think it's better to give a user information that their doing something wrong as early as possible.
Note, that's just in my experience though.. it's a big world.
It may be more that you presently require, but one alternative is to save the data in a database:
http://msdn.microsoft.com/en-us/library/6tc47t75%28v=VS.100%29.aspx
http://www.asp.net/web-forms/videos/how-do-i/how-do-i-set-up-the-sql-membership-provider
I have a web page that contains a textbox and a submit button. When the user edits the text in the textbox and clicks another link (not the submit button) how do I display the 'Are you sure you want to navigate away from this page' popup message?
I have researched this on the net and found a few javascript examples. Is this the only way you can do this? If not, what is the best way to do it?
This is one of the multiple ways to achieve the same thing
function goodbye(e) {
if(!e) e = window.event;
//e.cancelBubble is supported by IE - this will kill the bubbling process.
e.cancelBubble = true;
e.returnValue = 'You sure you want to leave?'; //This is displayed on the dialog
//e.stopPropagation works in Firefox.
if (e.stopPropagation) {
e.stopPropagation();
e.preventDefault();
}
}
window.onbeforeunload=goodbye;
got it from here open js
Only the unload() event will work on JS. You can't manage it on the server.
Check out the answer to this other question on SO, it is very similar to your question
How to show the "Are you sure you want to navigate away from this page?" when changes committed?
Simple solution
window.onbeforeunload = confirmExit;
function confirmExit() {
return "Are you sure you want to leave this page?";
}
4guysFromRolla.com - Prompting a user to Save when Leaving a Page
You cannot use the onbeforeunload window method as it gets triggered by multiple ways like back and forth browser navigation links, refreshing the page, closing of the page, clicking on the links.
What i feel you have to bind the link tag for which you want display the navigation away message and then use the function for the status message display
window.addEvent('domready',function(){
$$('a').addEvent('click', function(e) {
//leaving(); function u wrote for displaying message
});
});
function leaving(e) {
if(!e)
e = window.event;
// return code for the displaying message
}
If you want to do this in a way that guarantees it will work on almost all browsers, use the JQuery library. The following describes the unload event.
http://www.w3schools.com/jquery/event_unload.asp
It's exactly for purposes like yours.
Just to elaborate a little, you would have to download the jquery js library and reference it in your project/page, but you'll probably want to do that eventually anyway.
If you want to control this from the server side, you can dynamically emit the jquery call in the OnPreRender.
Look into Jquery's .beforeunload property. Here is an example:
$(window).bind('beforeunload', function(){ return 'Click OK to exit'; });
Please note, beforeunload canot prevent a page from unloading or redirect it to another page for obvious reasons; it would be too easy to abuse. Also if you just want to run a function before unloading, try the following:
$(window).unload(function(){ alert('Bye.'); });
Finally, don't forget to referrence jQuery in your head tag by using:
<script src="http://code.jquery.com/jquery-latest.min.js" type="text/javascript"></script>
The above gets you the latest version from the internet and saves you the trouble to download it, and of course you can do so optionally, but I am just trying to get your thing to work asap.
Oh, I also found an example for you. Click here to see a page that calls a function before it closes. Hope this helps bud.
I was able to get this to work with Andrei G's answer. I would add on that to get it to work in Chrome, add this to the end of his goodbye function:
return "";
in my application i have the playvideo page where video will play, below that i have the option for sharing the video like adding to favorite ,playlist and sending mail.
when i click on any of the link the page is postbacking and video will start from the first.
i place update panel for link button even though it is not working (video is playing from the first i.e., page is postbacking. can u help me. thank you
Actually, the part of page that is within the UpdatePanel does the postback. Make sure you have only those controls(for instance, your links) inside the UpdatePanel.
Alternatively, you can use multiple UpdatePanels; for instance one for your video and one for the links. In this case note that, when one UpdatePanel gets updated other UpdatePanels also gets updated, which you may not want; so all you have to do then is to mark the UpdateMode property to Conditional and call YourDesiredUpdatePanel.Update() method manually - whenever required.
Btw, updating selected portions of the page also reduces the load on the server
Or you may want to look into using client callbacks instead of a postback. But since client callback uses XMLHTTP, which means Microsoft implementation of AJAX, therefore callbacks are just awesome as long as your are working with IE.
You might want to try taking advantage of Page Methods to do the work you need done server side.
http://encosia.com/2008/05/29/using-jquery-to-directly-call-aspnet-ajax-page-methods/
Also, if you want to prevent a control from posting back, you can add return false to the end of your javascript onclick event on the control.
For example, if you had an asp button you were using you could do this:
<asp:Button ID="myButton" runat="server" OnClientClick="DoThingsInJavascript(); return false;" />
Or if you were just using a standard button you could say:
<input type="button" onclick="DoThingsInJavascript(); return false;" />
I've never really liked the update panel and I have sometimes found it's behaviour awful. Have you thought of trying something like a proper ajax call from Javascript