Besides the concept of actions, which are implementations of the command pattern, Delphi also contains a well—integrated implementation of an observer pattern in the form of the LiveBindings mechanism.
The observer pattern is discussed in Chapter 7, Iterator, Visitor, Observer, and Memento.
LiveBindings, which is partially implemented in the IDE and partially in the runtime library, helps create applications without any line of code. Of course, that is only the best—case scenario and in almost any useful application you will have to write some code.
The LiveBindings mechanism is very powerful and quite complicated, so I cannot do it any real honor on these few pages. I will therefore present just a short recipe, which will show you how to use LiveBindings to display data from a table. It will hopefully give you a taste of LiveBindings and the possibilities behind it. If you would like to learn more, I'd recommend reading an extensive white paper that was published by Embarcadero...