About SendMessage() - Cpp

[AL VA]

Hi,

First, i Hope it is the good section where i posted !

I'm lookin for any help, i tried to get help on developpez.com or
siteduzero.com but nobody is able to help me ! Im gettin crazy i
really dont succeed.

I'm trying to send the TAB key for example via SendMessage to Notepad

=>

SendMessage(NotepadHandle, WM_KEYDOWN, VK_TAB,0);
SendMessage(NotepadHandle, WM_KEYUP , VK_TAB,0);

<=

Why it doesnt work ?

Thank you, f...@hotmail.fr.