Hi everyone
I would like to know how can I subclass a window in a different process, to
manipulate its behavior?

I have some kind of idea that I have to use Windows Hooks, or subclassing or
both of them.

but I am not sure how to do it?

I know that most of the manipulation procedures should be in a DLL, that
should be injected in the window process. but I don't know how.

Can somebody please help me with this problem.   Any hint or tip will be
greatly appreciated, maybe a book name or address to a web site, or a even
better some code samples.

Best regards.

It depends on what you need to do. Whether you only need to subclass a
specific windows or everywindows.

In the first case you can use regular subclassing, getting the windows
function and so on. The only thing is that the code must be in a DLL that
you place in the other process calling SetWindowsHookEx.

In the second case you still need the dll and a call to SetWindowsHookEx but
you must code everything in the callback function.

Fill free to cantact me for more information.

Alessandro

Use SetWindowLong to set the GWL_WNDPROC of the window to point to your
"subclass" window proc.  Your subclass window proc should pass any messages
that it doesn't completely intercept on to the previous window proc using
CallWindowProc(pointer to previous wndproc is obtained before you changed
the GWL_WNDPROC, using GetWindowLong) .  Also, intercept WM_DESTROY and in
there you should restore the previous value of GWL_WNDPROC

That's all there is to it.

If you wanna subclass a whole bunch of windows, consider using the window
message hook stuff.