ASP.NET Dynamic Page Controls: Is it possible to bind events AFTER Page.Load?

Question

I have a site that I am currently working on in ASP.NET 2.0 using the usual WebForm stuff and ASP.NET AJAX 1.0. Is it possible to bind an event to a dynamically created control after the Page.Load event?

I have a table <td> element that I am dynamically creating similarly to this code:

' Create Link Button
lnk.ID = String.Format("lnkDetails_{0}", dr("Id"))
lnk.Text = dr("Name").ToString()
lnk.CommandArgument = dr("Id").ToString()
AddHandler lnk.Click, AddressOf DetailsLink_Click
cName.Controls.Add(lnk)

This this code is looped over for each row in a database (and of course more cells are added to the table, including an ImageButton with an event. The events work flawlessly when I execute this code during events leading up to and including Page.Load. I need to be able to fill this table with current data, which is updated during a btnClick Event elsewhere on the page, which occurs after this Page_Load event, so I am populating with old data. If I change this code to Page.LoadComplete, events stop working.

This data is a summary display of various components of an application, things like somebody's name, which when updated on a 'detail' form, updates the database by partial postback (a requirement), then it needs to show the update in this 'summary' section after an update. Currently it takes 2 postbacks to actually see the change in the 'summary' section, so effectively the summary is 1 step behind the changes (clear as mud?)

What would be the best way for me to populate this table with current data (which is available during/after Page.LoadComplete), but still have an event fire when a link is clicked (the event causes an UpdatePanel to display the 'detail' form).

I also have jQuery at my disposal and the usual ASP.NET AJAX methods, also javascript is a requirement for the website, so I do not need to degrade for unsupported browsers.

This is my first ASP.NET web application and need some help figuring out the best way to make this happen (I'm well versed in PHP, Django and the usual ways to do web forms - things like having multiple forms on one page o_O).

Update:

There really isn't a good way to bind control events to controls after Page_Load. The overall architecture of the pages is there is one ASP.NET form encompassing the entire page, there is only 1 aspx page. I am using master pages (however it doesn't have any obvious implications to my issue).

The page is split into a left and right 'pane', the left is a summary of all the data (in an update panel), the right 'pane' has 6 'tabs' implemented each as their own user control, each with several form fields and an update button all in it's own UpdatePanel.

An update on any of these tabs only refreshes the summary panel (UpdatePanel.update()) and its own panel. The 'refreshing' and event binding of dynamic controls of the summary from the db happens during Page_Load and the Update Button event updates db data. (The control event happens after Page_Load). I want to avoid doing a double post to get the summary to update, any thoughts are helpful.

Answer 1

You have to add the controls before Page.Load in order to maintain ViewState between postbacks, so use the OnInit event handler for that.

But once they're added, you should be able to bind event handlers (such as OnClick) at any point during or after the Page.Load... for example in your grid's ItemDataBound (or something like) or in the Page.PreRender.

Answer 2

You need to postback the whole page after your data changes in the 'btnClick Event elsewhere on the page'. It sounds like you have an UpdatePanel and it sounds like this is catching the postback of your btnClick event handler. Put the btnClick outside the UpdatePanel or change its triggers so that your btnClick forces a postback/refresh of your data. Or, redesign your table so it's AJAXly-refreshed when you click on btnClick, it's hard to get you more details without knowing more about the structure of your page and controls.

Good luck!

Answer 3

You can bind to an event whenever you want. It's just a simple event after all. But not all places might be suitable because you have to take into account when the event fires. And in most cases this happens between Page_Load and Page_PreRender. That includes the click event on a LinkButton. In general, I would recommend to add your dynamically created controls in the Page_Init stage.

Answer 4

Hello

I have the same problem and i found this solution:

have a look at: http://geekswithblogs.net/rashid/archive/2007/08/11/loading-user-control-dynamically-in-updatepanel.aspx

hope that it can help you