Extender

An extender is a kind of Ajax-enabled control to provide a list of script descriptors and script references. The purpose of an extender is to wire a client component to an existing server control. An extender acts as an external object and attaches itself to a server control. This can also be done alternatively by deriving from a base class. Let’s think of a simple client component that does an auto-complete functionality similar to that of Google Suggest and wire this to a TextBox server control. All we have to do is create a class AutoComplete with script descriptors and script references and derive it from the TextBox class. But the simple way is to use an external object and wire to the server control. Figure 10.2 displays the model of an extender generating script descriptors and script references.