How can I help the lazarus team

[Mark Derricutt]

On Wed, 3 Nov 1999, Shane Miller wrote:

> TCustomForm's wndproc directly from another function because it is a
> "protected" method.  Therefore I assume I need to ise either the class
> in Delphi called WINDOWCLASS or something similiar to call the
> wndproc.  I am still looking into this and would appreciate any help
> from ANYONE!.  :-)

The Delphi help file says:

When an application creates a window, it registers a window procedure with
the Windows kernel. The window procedure is the routine that handles
messages for the window. Traditionally, the window procedure contains a
huge case statement with entries for each message the window has to
handle. Keep in mind that window in this sense means just about anything
on the screen: each window, each control, and so on. Every time you create
a new type of window, you have to create a complete window procedure.

Delphi simplifies message dispatching in several ways:

o  Each component inherits a complete message-dispatching system.
o  The dispatch system has default handling. You define handlers only
   for messages you need to respond to specially.
o  You can modify small parts of the message-handling and rely on
   inherited methods for most processing.

The greatest benefit of this message dispatch system is that you can
safely send any message to any component at any time. If the component
does not have a handler defined for the message, the default handling
takes care of it, usually by ignoring the message.

Tracing the flow of messages

Delphi registers a method called MainWndProc as the window procedure for
each type of component in an application. MainWndProc contains an
exception-handling block, passing the message structure from Windows to a
virtual method called WndProc and handling any exceptions by calling the
application classs HandleException method.
MainWndProc is a nonvirtual method that contains no special handling for
any particular messages. Customizations take place in WndProc, since each
component type can override the method to suit its particular needs.

WndProc methods check for any special conditions that affect their
processing so they can trap unwanted messages. For example, while being
dragged, components ignore keyboard events, so the WndProc method of
TWinControl passes along keyboard events only if the component is not
being dragged. Ultimately, WndProc calls Dispatch, a nonvirtual method
inherited from TObject, which determines which method to call to handle
the message.

Dispatch uses the Msg field of the message structure to determine how to
dispatch a particular message. If the component defines a handler for that
particular message, Dispatch calls the method. If the component does not
define a handler for that message, Dispatch calls DefaultHandler.

.end topic.

I'm sure theres more in the helpfiles somewhere as well.

Mark

-- 
Mark Derricutt
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