Re: Button for continous 'increase' function

Sure, there's almost always "a way". Off-hand, here's what comes to mind. The BN_CLICKED
notification is sent when you release the left mouse button after having pushed it down over the
button control; this is too late for what you want. The mouse messages, WM_LBUTTONDOWN and
WM_LBUTTONUP, are sent to the window for which the mouse click is in the client area (assuming no
others have captured the mouse). That means when you click on a pushbutton control, that control
window is sent these messages.

If you derive a class from CButton, and use this derived class for the All Layers Increase button,
you can add handlers for WM_LBUTTONDOWN and WM_LBUTTONUP. In the button down handler, set a timer
(SetTimer) that is fired at some brief interval (this depends on how rapid you want the increase to
happen while the button is down). Whenever the handler for the WM_TIMER messages is invoked in your
derived button class, it can send the BN_CLICKED notification to the parent dialog box via a
WM_COMMAND message. This is basically simulating numerous button clicks at a normal interval
(dictated by the timer). In the handler for the WM_LBUTTONUP, just kill the timer (KillTimer).

BN_CLICKED Notification ():
http://msdn.microsoft.com/en-us/library/bb761825.aspx
WM_COMMAND Notification ():
http://msdn.microsoft.com/en-us/library/ms647591(VS.85).aspx

Warning, I haven't actually tried this -- it just seems very reasonable.

Scot

"blackbiscuit" <infozyzhang@gmail.com> wrote in message
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