File: Introducction_p4a

p4a_Application:
The application itself, the receptor of the user events and the container of all objects

p4a_Control:
Base class
|
|---------------->>p4a_BarMenu:
|                   menu bar containing (at the moment) only 'main items'.
|
|---------------->>p4a_ListView:
|                   List View to represent rows of a table or an array. 
|                   It can responds to several user events like column
|                   click, row click, etc
|
|---------------->>p4a_Form:
|                  Form to maintain and display data of a source that can 
|                   be a table or an array, it has events like update,
|                   insert, next, previous, unlock...
|
|---------------->>p4a_SimpleForm:
|                  Form not linked to a 'DataSource' object, it only has 
|                  two events, one of this sends all data fields to the 
|                  server-side.
|
|---------------->>p4a_Panel:
|                The other container of the p4a framework. This is an 
|                important object that contains other objects, in the same 
|                 way of p4a_Application, and it controls the layout 
|                 disposition of all ones. One important thing of this 
|               container is that it can be invisible, doing, by this way, 
|                all its objects invisibles so. This object acts as 
|                 the 'frame' control in Visual Basic.
|
|------------------>>p4a_Label:
|                    A simple label that contains optionally an image.
|
|------------------>>p4a_PlainButton:
|                     A simple button that responds to the click event and 
|                     can have an image.
|

p4a_DataSource:
Object not visible that has to be passed to a Form or a ListView and that implements some methods like getRecords. The source of the data can be a table in a database or whatever that implements the interface methods of DataSource.