PageCounter Object for ScrollViews

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Environment: The demo project was created with VC++ 6.0 SP1

When scrolling in a document that consists of quite a lot pages it might be helpful for the user to get an information which page of the document would be displayed if he/she >would release to slider of the scrollbar at a certain position.
Microsoft Word has such a feature. It’s a tooltip-like window that displays the page number that corresponds to the current position of the slider during scrolling.

I implemented a class named CScrollViewPageCounter that displays such a page number in a window that looks like a tooltip-window. If you have a look at the source code you’ll find out that it was quite easy to implement. The code itself is self-explanatory…

HOW TO USE

1. Add the files ScrollViewPageCounter.h and ScrollViewPageCounter.cpp to your project.

2. Add a new member m_pScrollViewPageCounter to your scroll view class.

CScrollViewPageCounter*

m_pScrollViewPageCounter;

 #include “ScrollViewPageCounter.h”

3. Create the page counter object in CYourScrollView::OnInitialUpdate()

BOOL CYourScrollView::PreCreateWindow(CREATESTRUCT& cs)

{

 CScrollView::OnInitialUpdate();

 // Instantiate the counter object

 m_pScrollViewPageCounter = new CScrollViewPageCounter( this );

 }

4. Add a command handler for the message WM_VSCROLL:

 void CYourScrollView::OnVScroll(UINT SBCode, UINT nPos, CScrollBar* pScrollBar)

{

 if ( nSBCode == SB_THUMBTRACK )

 {

  // calculate page number (insert your algorithm here)

 UINT uiPageNumber = (UINT) (nPos / 10) + 1;

  // display page number

  m_pScrollViewPageCounter->DisplayPageNumber( uiPageNumber );

 }
 // when scrolling is finished we have to hide the page counter

 if ( nSBCode == SB_ENDSCROLL )

 m_pScrollViewPageCounter->Reset();
 CScrollView::OnVScroll(nSBCode, nPos, pScrollBar);

}

Download demo project – 33 KB

Download source – 3 KB

Date Last Updated: April 16, 1999