Designing and Developing ASP.NET 4 Web Apps (Exam 70-519) Tutorials
Client Side ASP.NET / UpdatePanel Control
Visitors to VTC.com will be able to view all introductory videos for each training course.
Free Trial Members will gain access to first three chapters for each training course.
Full Access Members have full access to VTC.com�s entire library of video tutorials.
Learn More
Subtitles of the Movie (Designing and Developing ASP.NET 4 Web Apps (Exam 70-519) / Client Side ASP.NET / UpdatePanel Control)
The UpdatePanel Control is the workhorse for the ASP.NET AJAX functionality. This guy performs the heavy lifting when partial updates are needed and partial updates are really the predominant reason that we got into AJAX anyway. And so what the UpdatePanel does is it performs PostBacks to the server for all the controls that are wrapped inside the UpdatePanel Control. Now what it's actually doing is, is it's just sitting there, it's watching the controls that have been placed inside it and anytime any of those controls tries to perform a PostBack to the server, it intercepts those PostBack Calls, puts them into Asynchronous Call and sends them and doesn't do it for the whole page and it, this Asynchronous Call makes for some pretty cool stuff here, because only the controls contained by that UpdatePanel are updated and so as a result the rest of our page, number 1 continues to work. We can type and work on it and we don't get that irritating page flash and all that. Now let's think about something that could happen and this could be a scenario question you see on the exam, it could be a question you have in real life and that is, okay, so I've got all this cool ASP.NET AJAX functionality, well what happens when the end-user or the browser causes a problem? What if the end-user has an old browser and it doesn't support AJAX or what if they've got JavaScript disabled in the browser and AJAX won't work? Well all that's going to happen is you're going to get your normal full page PostBacks. You haven't lost any functionality, your PostBacks will still work because that's Server Side, it's browser independent, but it's just that your Client Side JavaScript stuff's not going to function like you thought it would. Now here's another problem that I just want to mention here. I don't think you'll see this on the exam, but you could. And that is that partial page updates can go unnoticed especially when we get into to talking about Triggers and I'll talk about those later. But if I'm doing a partial page update, you may work somewhere else on a Trigger, something that Triggers an update and it'll happen fast and since the page is not flashing, you won't notice that anything updated. So keep that in mind as you use this, if something's changing and the user needs to be aware of it, you may want to let them know and the way you can do that, is you can hook into or you can code into the Page Request Manager with JavaScript and it fires each time the page loads. Now that includes Asynchronous Calls that are launched by UpdatePanel. So if you want to flash up a little page or an alert or change a color or do something to let somebody know that hey, something you just did here updated something, you know, numbers have been updated or something like that. Keep that in mind. Now the UpdatePanel has some properties that provide more specific functionalities and we're going to hit on a couple of them here in this course in separate videos, so I'll do a separate video on Conditional Updates and talk about those and then do an update, maybe even a demo on Triggers and how they work along with the UpdatePanel Control. So that's a quick overview of UpdatePanel Control and we will touch on Conditional Updates and Triggers in separate videos so join me there.
Tutorial Information
| Course: | Designing and Developing ASP.NET 4 Web Apps (Exam 70-519) |
| Author: | Mark Long |
| SKU: | 34292 |
| ISBN: | 978-1-61866-029-9 |
| Release Date: | 2011-12-31 |
| Duration: | 8.5 hrs / 108 lessons |
| Work Files: |
Yes |
| Captions: | No |
| Compatibility: |
Vista/XP/2000, OS X, Linux QuickTime 7, Flash 8 |
VTC Sign up & Benefits
- Unlimited Access
- 81,350 Video Tutorials (14,200 free)
- Video Available as Flash or QuickTime
- Over 715 Courses
- $30 for One Month Access
- Multi-User Discounts Available
