The Code Is Always Associated With a Component
A Visual LANSA application consists of several individual event-routines which are associated with specific components.
This is quite different from a LANSA function which is a single program in which DISPLAY, REQUEST and POP_UP commands create entire screens. These screens are always processed as a whole.
In contrast, in Visual LANSA every component on a form can have its own event routine which gets executed independently when the user performs a certain action. Because of this, you can create dynamic interfaces which instantly respond to user actions. For example you can disable and enable controls depending on the user's choices:
In a LANSA function you cannot change the screen dynamically because it is processed as a whole. The information entered on a screen is processed and validated only when the user clicks on the OK button:
Ý 6.9.2 What Is Different Between Event-Driven and Procedural Programs?