detect/control changes in built-in scrollbar of RichTextBox

mervbit
mervbit used Ask the Experts™
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I would like to synchronize the scrollbars of several different RichTextboxes in an application.  But the only scrollbar properties available in the RichTextbox property set are whether or not scrollbars are enabled.  There doesn't even seem to be any event generated by the movement of a RTBox scrollbar.  Is there any way my code can access and change these scrollbar properties in the same way that is available for VB stand-alone scrollbars?

--merv
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The only way I can think of to do this is to subclass the message stream going to the Rich TextBoxes.  You are looking for messages:
WM_VSCROLL (SB_LINEDOWN, SB_LINEUP, SB_THUMBTRACK - used for when they grab the thumb and drag it)  WPARAM =1  means scrolled single line.  WPARAM = 8 means scrolled uwing a click inside the scrollbar body.

If you don't know how to subclass, I can provide that code for you, but you're going to have to play around with the messages till you get it right.  You will also have to send the same messages you are receiving to the other richtextboxes.

 

Author

Commented:
This is a bit involved for me -- given that I don't even know what "sub-classing a message stream" is!  If it is really simple, I'm game to give it a shot, but since this is a non-critical part of my application, I'm inclined to just drop it.  What I'm saying is:  don't spend a lot of time coming up with code for me unless you can do it in a couple minutes or less.

--merv
Here's a site describing subclassing.  Since you're ready to drop the issue, it wouldn't be worth it to go through and try to trap the correct messages and perform the synchronization.  It would probably take about a half-hour to get there from here, but thought you might like to see the subclassing code.  It would simply be a matter of trapping the messages I said, but the challenge will be in sending the messages to the other RTB controls.
http://www.andreavb.com/tip020015.html
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Author

Commented:
Thanks for the link -- I checked it out, and it was way over my head!  Thanks anyway.

--merv
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