Advanced ASP.NET AJAX Server Controls For .NET Framework 3.5

     In this book "Advanced ASP.NET AJAX Server Controls For .NET Framework 3.5" , we're going to teach you how to use ASP.NET AJAX to create server controls that encapsulate Ajax functionality.

     Server controls are an integral aspect of every ASP.NET application we build. They encapsulate browser appearance and server functionality in a reusable object. They can be used across multiple pages within a single ASP.NET application as well as across multiple ASP.NET applications. ASP.NET comes with a lot of prebuilt server controls. We have simple controls such as the label and we have complex controls such as the GridView. We also have the ability to create our own server controls to meet a need not met by one of the existing controls by inheriting from the appropriate base class and overriding its methods as needed. This model of using server controls to encapsulate browser appearance and server functionality has served our needs well since the inception of ASP.NET 1.0, but our server control needs are changing. A new server control need that has recently surfaced is the ability to incorporate Ajax functionality directly into the server control. This need arose because our web applications need to be more responsive and visually interactive than the traditional ASP.NET repaint-the-entire-screen model and therefore the traditional server control supplies. This requirement has emerged because users are using web sites such as Gmail, Live.com, Yahoo! Mail, and others that don't repaint the screen every time they click a button or need to receive fresh data. Rather, they rely on Ajax to fetch fresh data and then update or add to a portion of the screen based upon that data. Because these web sites are heavily used and users really enjoy their experience while using these websites they expect other web sites to perform with the same elegance as they do. When a web site doesn't perform with the same elegance the user will often move onto another web site that does. Those popular applications have raised the bar for what is an acceptably user-friendly web site. Because our users are demanding a web site experience that essentially uses Ajax and we build our ASP.NET web sites using server controls, we need a way of easily creating server controls that not only encapsulate browser appearance and server functionality, but also include Ajax functionality so that the server control itself is Ajax-enabled. Taking a step back for a moment, unlike other technologies you might have read books on, ASP.NET AJAX server controls don't provide you with anything that you couldn't already do. We've always been able to embed Ajax-functionality into server controls ... it was just a real pain. There were a few different methods we could use to include the JavaScript with our server control such as embedding it as a resource, but we eventually ended up having to do the same three tasks. To make our server control have some serious client capabilities we always had to concatenate strings together to form JavaScript statements and functions, write browser sniffing statements to make sure that the JavaScript was cross-browser compatible, and add attributes or render out Html that attached the JavaScript functionality to the client versions of our server controls. It wasn't impossible, but it was error-prone and there was always this mingling of server code and JavaScript that was hard to maintain and even harder to read. Furthermore, if you had multiple server controls that had client capabilities it was difficult (but not impossible) to ensure that the client functions that each server control required didn't overwrite each other when rendered on the browser. Tracking down that problem was always a fun hour or so. The difficulty grew exponentially if we wanted to include a mechanism for asynchronously communicating with the server when the user pressed a button embedded in the server control. Even with a helper communication library there were always tricks to getting your control to communicate properly with the server. These hindrances were problematic enough to lead to some bad programming habits and bad code as well as scare programmers away from even attempting to include Ajax-functionality in their server controls. These problems are what Microsoft's ASP.NET AJAX solves. In this book, we're going to teach you how to use ASP.NET AJAX to create server controls that encapsulate Ajax functionality. ASP.NET AJAX provides both server and client programming constructs that make adding Ajax-capabilities to our server controls easy. Not to sound cliché, but with ASP.NET AJAX reducing the complexity of adding Ajax-capabilities to our server controls, we're able to create server controls whose Ajax capabilities are only limited by our creativity. If we want to listbox that self-updates with fresh data, if we want a type-ahead textbox that dynamically populates from the server, or if we want a button submits an address for verification we can easily accomplish this through ASP.NET AJAX. 648 pages | Addison-Wesley Professional; 1 edition (July 6, 2008) | ISBN: 0321514440 | PDF | 5 Mb

Format: .pdf Page: 648 Read: 22 Added: Oct 08th 2008 Category: .NET Publisher: free-ebooks Homepage: http://freebooks.download-123.com/ Bookmark:   Report Dead Download Link Alternative Download: This ebook is also availabe on Usenext, Recommend you to download it from Usenext.

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