Programming Atlas

Chapter 11. Extending Controls

In addition to providing controls of its own, Atlas comes with special markup elements that can enrich existing ASP.NET web controls by letting you add new, client-side features, such as drag and drop and autocompletion. Using these extensions is quite simple, and their effects are astonishing.

In addition, Atlas provides a new control, the UpdatePanel control, that lets you confine postbacks to a particular area of a page, such as the input fields of a form. The UpdatePanel control can, for instance, get data from a web service, such as a stock ticker or weather service, and continually updates its result.

Using these controls can save you a lot of coding, testing, and debugging time as well as frustration, and they make up some of the most exciting features of the Atlas framework.

In this chapter, you’ll learn how to use control extensions and client-side drag and drop and autocompletion, and you’ll also see how you can use the UpdatePanel control to cut down on postbacks of an entire page and improve the responsiveness of your application.

Adding Drag and Drop to a Control

In the early days of ASP.NET 2.0, drag-and-drop demos were common and popular. However, they were originally targeted at Web Parts development, which is also available with Atlas (see Chapter 3). One of the problems with the drag-and-drop effect in Web Parts controls was the fact that this worked only in Internet Explorer, unless you used the Atlas Web Parts.

Enter Atlas. One ...