4.1 Component Concepts
Visual LANSA extends the LANSA repository to include components in addition to fields and files. This object-oriented component model provides the foundation for user-centered, event-driven applications. However, in Visual LANSA the object-oriented paradigm is implemented in a simple way to allow you to focus on productivity and business goals.
Components are programming objects that support properties, events and methods. LANSA components are stored in the LANSA Repository. With components, you create event-driven applications.
Visual LANSA has many user definable 4.3 Component Types. The most common component is a 4.3.1 Form which corresponds to a window of an application. 4.3.2 Reusable Part parts contain controls and code which can be reused in forms (or other reusable parts).
Properties
All Visual LANSA components have properties which define their characteristics. Most properties deal with the way a component is displayed on the screen: its size, color, and whether it is visible or not. You can set the properties when you are designing your application, or programmatically when the application is running. Often you do not need to change any of the default property values.
Events
An event is a thing that happens or takes place. Typically an event is any action the user takes. The most common event is click (when the user clicks on a component with the mouse). You could for example define a button 'Print' and write code for the button's click event to print something. When the application is running, every time your user clicks on the Print button the print routine will be executed.
Methods
A method is how you tell a component to do something. For example to display a form, you use the ShowForm method:
INVOKE #FormB.ShowForm
You can also define custom methods to make a component perform an action.
Also See