Although using controls for repeating content is already quite useful, they become even more useful
when you add custom logic to them. By adding public properties or methods to a user control, you
can influence its behavior at run time. When you add a property to a user control, it becomes available
automatically in IntelliSense and in the Properties Grid for the control in the page you’re working
with, making it easy to change the behavior from another file like a page.