OpenEuphoria

Re: Getting Combo Box Drop Down Button hWnd?

• Posted by Larry Miller <larrymiller at sasktel.net> Jun 11, 2005
• 572 views

I have been following the ongoing coversation between Al and Derek with
interest. I would like to add that there is a potential problem with setting
the GWL_USERDATA field on some controls. With the large marjority of controls,
all those currently supported by WIn32Lib, there is no problem. But setting 
this field on an IP Address control, "SysIPAddress32" class, has caused a
very serious problem for me. After this field has been set any reference to
the control prior to the main window opening causes a machine exception. 
Otherwise an error is generated on startup. Also, the SetWindowLong funtion does
not return 0 when this is done. The only window styles specified are WS_CHILD 
and WS_VISIBLE. If the function is removed the control opens and functions 
normally. I have noticed this only with this control type. 
This is on Windows 2000 with SP4 and IE6.

It appears that this control is using the GWL_USERDATA field for it's own use. 
Is it possible that I am doing something wrong, or is this not an entirely 
legitimate thing to do? MSDN does not specifically mention it's use with 
controls, only with windows.

Larry Miller