[Gambas-user] New event interception mechanism

[Benoit Minisini]

Hi,

I have just implemented a new event interception mechanism in Gambas.

This mechanism is based on a new class named 'Observer'. To intercept the 
events raised by an object, just do:

DIM hObserver AS Observer
hObserver = NEW Observer(TheObject) AS "AnyName"

Each time 'TheObject' will raise an event named 'ObjectEvent', then the 
observer will catch it first, and then call the event handler 
named 'AnyName_ObjectEvent', as if the observer object has raised this event 
itself.

If you use STOP EVENT in the observer event handler, then the official parent 
of the object will never see the event.

If you define several observers on the same object, they will get the event in 
their definition order.

This mechanism will allow to extend easily existing controls with Gambas. 

As an example, you will find in gb.form a new control named 'TableView' (if 
you have a better name just tell me). It is an editable GridView.

This control is written in Gambas, inherits GridView, and allows cells to be 
edited by intercepting events, and defining a few new methods.

To use it, just call the new 'Edit' method when you want to edit the current 
cell.

This method takes optional parameters: the first is a list of possible values, 
if you want to edit the cell with a ComboBox instead of a TextBox, and the 
second tells if the ComboBox must be read-only or not.

Regards,

-- 
Benoit Minisini