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How do VFP controls fake it?
Message
Information générale
Forum:
Visual FoxPro
Catégorie:
Autre
Versions des environnements
Visual FoxPro:
VFP 9
OS:
Windows XP SP2
Network:
Windows 2000 Server
Database:
Visual FoxPro
Divers
Thread ID:
01037136
Message ID:
01037203
Vues:
16
>I'm just curious because of what Fred Taylor told me that VFP Native controls are not actual windowed controls but bitmap representations of windowed controls. Please refer to:
>Thread#1035003
>Message#1037110
>
>So I was wondering how the events are fired and the control message looping is handled?
>


Hi Dawa,

Just a thought. At first, all windows messages is actually handled by the form (or the topmost control that is an actual window control). Then VFP altered the message to decide what to do next. If you look at the SysTray sample from VFP, you will noticed there is a comments like this:
"MouseWheel event is the only VFP event that doesn't alter..."

For instance, The MouseMove event is actually a WM_MOUSEMOVE that is received on VFP form. Then the form looked further if there is any VFP control underneath. If there is a control then VFP will process the next step, and so on.

About how VFP drawing/render the control itself I have no idea <*g*>. But if you want to know how to draw something on the window, read GDI/GDI+ documentation at MSDN.

To see whether VFP control is a window control or not, you can use SPY++, WinSpy, or you can download my WinTracker on UT download area (file #27704)

Again, that's purely just a thought! :-)

Regards
Herman
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