Visual C++ and MFC Programming 2nd Edition

Visual C++ and MFC Fundamentals Chapter 17: Track-Based Controls

return TRUE; // return TRUE unless you set the focus to a control

}

2. Test the application and return to MSVC

17.3.5..Slider Events........................................................................................

On its own, the slider controls can send three notification messages:

?? The NM_OUTOFMEMORY message is sent when the slider has run out of

memory and could not complete a task

?? The NM_RELEASECAPTURE message is sent when the user releases the

mouse on the slider

?? The NM_CUSTOMDRAW message is used if you want to draw something on

the slider or you want to customize the appearance of the slider beyond what

Visual C++ proposes

For its functionality, the slider highly relies on its parent. When the user clicks the thumb

or any part of the slider, which causes it to slide, a scroll event is fired. If the slider is

horizontal, the CWnd::OnHScroll() event is sent. If the slider is vertical, the

CWnd::OnVScroll() event is sent.

Practical Learning: Scrolling a Slider Control

1. Change the OnPaint() event of the dialog class as follows:

void CCarInventory1Dlg::OnPaint()

{

int CurPos = m_CarSlider.GetPos() - 1;

CBitmap Bmp;

Bmp.LoadBitmap(Car[CurPos].CarPicture);

m_Make.Format("%s", Car[CurPos].Make);

m_Model.Format("%s", Car[CurPos].Model);

m_Year.Format("%d", Car[CurPos].CarYear);

m_Doors.Format("%d", Car[CurPos].Doors);

m_Picture.SetBitmap(Bmp);

UpdateData(FALSE);

...
}
2. Using either the ClassWizard (MSVC 6) or the Messages button , for the dialog,
generate the WM_HSCROLL message and implement it as follows:

void CSlider1Dlg::OnHScroll(UINT nSBCode, UINT nPos, CScrollBar* pScrollBar)

{

// TODO: Add your message handler code here and/or call default

Invalidate();

CDialog::OnHScroll(nSBCode, nPos, pScrollBar);

}

3. Test the application