ASP.NET 3.5 For Dummies®

15.1. Introducing the AJAX Control Toolkit

The AJAX Control Toolkit is a set of AJAX enhancements to existing ASP.NET controls. The project's goal is "to be the biggest and best collection of web-client components available." A group of developers within Microsoft started the toolkit and then opened it to volunteer contributors.

See Chapter 2 for instructions on downloading and installing the AJAX Control Toolkit.

AJAX extenders add dynamic capabilities to Microsoft's standard ASP.NET controls. For example, Figure 15-1 shows the toolkit's ValidatorCallout control. The ValidatorCallout control changes the behavior of ASP.NET validation controls (such as the RangeValidator), so the error message appears as a floating callout box rather than as flat text on the page. You can also include a custom icon, as you see in Figure 15-1.

An extender also makes changes to the affected control's Properties window by adding properties. As shown in Figure 15-2, an Extenders category is at the top, and within it, the list of extenders. (Figure 15-2 has only one extender, RangeValidator1_ValidatorCalloutExtender.)

Figure 15-1. The Validator Callout changes the validator's appearance.

Figure 15-2. An extended control has an Extenders category.

Under each extender's node, you find the added properties ...