Writing Custom Controls
In this section, you’ll create an extender that restricts input into an HTML text box to a set of predefined characters—functionality that HTML does not offer. The Atlas Control Toolkit provides a project template for Visual Web Developer that facilitates this work. You start by installing the template, and then you change it and add the logic for the new extender.
As you’ve probably noticed, the Atlas Control Toolkit comes as one DLL file that contains all of the controls. You will likewise need to compile code to create a custom control. Fortunately, the toolkit ships with a Visual Studio template that makes creating such extenders easy.
In the AtlasControlExtender folder created by the Atlas Control Toolkit installer, you will find a VSI file (AtlasControlExtender.vsi) that installs a package you can use to implement custom extenders. To install the package, just double-click the VSI file. The package contains project templates for both C# and Visual Basic (see Figure 14-7).
Figure 14-7. The Atlas control extender VSI installer
If you are using Visual Web Developer Express Edition, ...