ID Number: Q68584
3.00
WINDOWS
Summary:
Window subclassing is explained on page 1-17 of the "Microsoft Windows
Software Development Kit Reference Volume 1," in the section titled
"Window Subclassing."
At the end of that section, the following warning appears:
Note: An application should not attempt to create a window subclass
for standard Windows controls such as combo boxes and buttons.
This warning means that SetClassLong() should not be used to subclass
an entire standard control class. This would cause all controls of
that type (including controls in other applications) created while the
subclass was in effect to be subclassed.
SetWindowLong() can be used to subclass individual controls in your
application.
In addition, standard Windows controls should only be subclassed in
"non-intrusive" ways. Subclassing procedures that alter the appearance
of a control or that depend on undocumented messages or message
parameters could be incompatible with future versions of Windows.
More Information:
For more information on subclassing controls, query on the following
word:
subclassing
Charles Petzold's "Programming Windows" (Microsoft Press) contains a
sample program that shows how to subclass a standard control (in this
case, a scroll bar). In the Windows 2.x version of the book, the
sample is called COLORSCR; in the Windows 3.00 version, the sample is
called COLORS1.