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What does ScrollBar::SetPage do? [message #13893]

Thu, 31 January 2008 15:16

cbpporter
Messages: 1401
Registered: September 2007

Ultimate Contributor

Hi!

I'm trying to implement an optimized control which would allow the scrolling of virtually huge surfaces. This is why I just can't insert a control into a larger one with two scrollbars. I'm imlementing a "virtual" scroll mechanism.

I have two scrollbars (one vertical and one horizontal). I compute the difference between the dimensions of the control and the dimension of virtual area and set them to the maximum of each scrollbar with SetTotal. Then I'm trying to set a page size:

dx = ... 
scrHor.SetTotal(dx);
scrHor.SetPage(dx / 10);

This works fine, but it seems that the last page is only scrolled to some fixed margin (somewhat like the IntegralHeight property in ColumnList). I can't get the last pixels of the area to show. But if I use SetPage(1), I can access all the ranges from the scrollbar, allowing full scrolling of the surface. But now scrolling is done in steps of 1, so clicking on the scrollbar body is useless (not useless, but very slow with increments of 1).

Am I misunderstanding the use of SetPage? How can I set a page dimension, which does not lead to some inaccessible values near the end?

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