Develop Reference

refresh page of all connected users after event from one user- type auction

I am working with .NET for my project. I would like to know how to set a refresh of a page for the the people seeing this page when an event occurs.
For example, an auction: people have their page refreshed automatically with the new amount when someone bids.
I want to display the quantity available of an item in real time. So all the users know how many are left and it is updated as soon as one user purchases an item.

Sounds like a candidate for SignalR.

I think you are looking for a Timer.
You could call a server side function frequently to check if a new event occured (someone bids) and then display an update.
Some examples here.
You cannot trigger a refresh from server side - you need to do it the other way around - frequently check if something has changed.

You can do that with AJAX and setTimeOut(). Set a timer to trigger an AJAX let's say every 1 minute, and in the AJAX method you can check if there are not read Auctions or so, in other words, your logic, and if the conditions are satisfied, you can get the AJAX's return to perform, for example, a window.navigate("auctionspage.html"); and redirects the user to a specific page. Be sure to check that the user did read the page so he won't be redirected again in the next setTimeOut() call.

Is there a generally accepted way to pass data from one ASP.Net form to another after validation?

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

HTML and jQuery Information Passing Design

I am designing a webapp using ASP.NET and jQuery and I could use some advice.
Currently, the ASP.NET page renders an unknown number of elements that perform an action when clicked. Javascript on the front-end handles the click event based on which specific element was selected.
Each element is embedded with information that the javascript function requires. This informaion is added as extra attributes. So for example, a given element might look like
Link 123
jQuery then attaches a click event and uses the extrainformation attribute as a parameter for an internal function. Each element has 3-5 parameters.
This works great, but I have heard recently that it might not be best practice since it is not WC3 compliant. One possible solution would be for each element to directly call the internal javascript function with the necessary parameters. However this makes me uncomfortable because I lose the separation of concerns between rendering the page and executing the client-side logic.
Is there a better way to do this? Or maybe I'm just overthinking it?

Yes there is a better way, its called HTML5 Data Attributes you can access them from jQuery using the $.data() interface.
For Example:
//instead of
Link 123
//use
Link 123
//then access it like
var info = $('#123').data('info');
alert(info); //alerts: 'something important'
Basically anything starting with data- is stored as data about that element in the DOM, jQuery can access this data via the $.data() function.

How can I pass textbox value from usercontrol(ascx) to another page (aspx) using Server.Transfer()

I am writing one user control (webpart) in kentico. I want to pass textboxes' value from usercontrol to aspx page using Server.Transfer().
Can it be? If so, how can I do like that?
Best Regards,
Reds

I don't particularly like this method, I prefer to use Sessions to pass data between pages, but if you need to do this here how it's done according to the this page.
Here's TL;DR summary. It requires three scripts/pages:
Form.ascx - this will be the control that contains the text box value.
FormParsingScript.aspx (referenced in the Form.ascx in the Action attribute) - this will perform the actual Server.Transfer "FinalScript.aspx" call
FinalScript.aspx which will display the contents of Response.Form["TextBoxName"] (HTTP POST) or Response.QueryString["TextBoxName"] (HTTP GET)

How can I set a variable in my pages javascript based on my controller action in ASP.NET MVC?

So, I have a page that looks like the following:
alt text http://img704.imageshack.us/img704/5973/croppercapture3.png
This is my basic messaging inbox. I have 2 pages right now, Inbox and Sent (there will eventually be others). These both share the same View, and just have 2 different actions to populate the appropriate data.
The elements on the right-hand side (the message list) is a partial view which has its data populated based on my two controller actions Inbox(int? page) and Sent(int? Page).
So, I have one view "MessageView" and one partial view "MessageList" shared between Inbox/Sent.
However, I now have to get those arrow buttons ("<" ">") working using Ajax. I know how to use jQueries ajax calls well enough, and I know how to render the result of the action call (which returns a partial view).
The problem comes from the fact that the javascript that makes these pagination ajax calls needs to know two things:
What the current page is (whether it be /messages/inbox or /messages/sent)
What the current page is (specified in the query string, ie /messages/inbox?page=2).
Without knowing which page I'm on (Inbox or Sent), it wont know which url to make the ajax call on. Should it make the postback to /messages/inbox or to /messages/sent?
If I wasn't making these messages load with Ajax it would be as simple as loading the appropriate url into the link tags for the "<" and the ">" buttons. But I can't, because part of my requirements states that it must load the messages below without visibly refreshing to a new page.

In JavaScript you can check window.location.pathname to see the pathname section of the current’s page’s URL.
window.location.search gives you the query string.

When the user clicks the Inbox or Sent buttons, you need to rewrite the URLs in your arrows so that they point to the right place.