This sample uses native subclassing to monitor WM_WINDOWPOSCHANGING
notifications, and demonstrates how simple it is to "snap" a dialog to the edge
of the screen as the user drags it around. You've probably seen this effect in
numerous little utilities like
WinAmp. It's so subtle, many users wouldn't even notice it, but it
definitely adds a touch of polish to nearly any application.
CSnapDialog is implementated as a drop-in ready class which hooks any
given form in your app and completely handles all the "messy" details. You set
it up, quite simply, like this:
Private m_Snap As CSnapDialog
Private Sub Form_Load()
' Setting up is a snap!
Set m_Snap = New CSnapDialog
m_Snap.hWnd = Me.hWnd
m_Snap.SnapGap = 20 '(optional)
The optional SnapGap property (default: 15) sets the "snap tolerance" in
pixels. Anytime your user drags the form within this many pixels of the edge of
any monitor on their system, CSnapDialog snaps the form to the nearest
edge or corner. No teardown is required, as that's completely encapsulated
within the class.
This sample, or the one from which it originally derived, was published (or at least
peripherally mentioned) in the following article(s):
This sample uses the following API calls:
Don't see what you're looking for? Here's a
complete API cross-reference.
||Please, enjoy and learn from this sample. Include its code within your own projects, if you wish. But, in order to insure only the most recent code is available to all, I ask that you
don't share the sample by any form of mass distribution.
12Kb, Last Updated: Friday, March 28, 2008
The following resources may also be of interest:
- HookMe - Native subclassing technique for VB5/6. Extremely clean.
- HookXP - Demonstrates native Windows subclassing method with no risk of improper teardown. Very flexible!
- Monitors - Provides a collection of objects representing each monitor on the system, and a module of functions for monitor tricks.