dcsimg

Create an Active Cursor on the Scroll Bar

Environment: VC6 SP5, VC.NET, Windows 2000

This code enables you to change the cursor dynamically on the scroll bar of the window, with scrolling capabilities. The variable m_nCursorID is used to prevent multiple loading of the cursor.

CMyWnd is derived from CWnd.

UINT m_nCursorID;    //Current ID of the cursor resource

CMyWnd::CMyWnd()
{
  m_nCursorID = 0;
}

BOOL CMyWnd::OnSetCursor(CWnd* pWnd, UINT nHitTest, UINT message)
{
  if (nHitTest == HTVSCROLL)
  {
    //Change cursor on the vertical scroll bar
    if(m_nCursorID != IDC_VSCROLLBAR)
    {
      SetCursor(AfxGetApp()->LoadCursor(IDC_VSCROLLBAR));
      m_nCursorID = IDC_VSCROLLBAR;
    }
    return true;
  }
  else if (nHitTest == HTHSCROLL)
  {
    //Change cursor on the horizontal scroll bar
    if(m_nCursorID != IDC_HSCROLLBAR)
    {
      SetCursor(AfxGetApp()->LoadCursor(IDC_HSCROLLBAR));
      m_nCursorID = IDC_HSCROLLBAR;
    }
    return true;
  }
  else
  {
    if(m_nCursorID != 0) m_nCursorID = 0;
    return BaseClass::OnSetCursor(pWnd, nHitTest, message);
  }

}

void CMyWnd::OnVScroll(UINT nSBCode, UINT nPos,
                       CScrollBar* pScrollBar)
{
  switch (nSBCode) {
  case SB_THUMBTRACK:    //Drag scroll box to specified position
    if(m_nCursorID != IDC_VTHUMBTRACK)
    {
      SetCursor(AfxGetApp()->LoadCursor(IDC_VTHUMBTRACK));
      m_nCursorID = IDC_VTHUMBTRACK;
    }
    break;
  case SB_LINEDOWN:      //Scroll one line down
    if(GetScrollPos(SB_VERT) == GetScrollLimit(SB_VERT))
    {
      if(m_nCursorID != IDC_VLINEDOWN_DISABLE)
      {
        SetCursor(AfxGetApp()->LoadCursor(IDC_VLINEDOWN_DISABLE));
        m_nCursorID = IDC_VLINEDOWN_DISABLE;
      }
    }
    else
    {
      if(m_nCursorID != IDC_VLINEDOWN)
      {
        SetCursor(AfxGetApp()->LoadCursor(IDC_VLINEDOWN));
        m_nCursorID = IDC_VLINEDOWN;
      }
      }
    break;
  case SB_LINEUP:        //Scroll one line up
    SCROLLINFO  info;
    info.cbSize = sizeof(SCROLLINFO);
    GetScrollInfo(SB_VERT, &info);
    if(info.nPos == info.nMin)
    {
      if(m_nCursorID != IDC_VLINEUP_DISABLE)
      {
        SetCursor(AfxGetApp()->LoadCursor(IDC_VLINEUP_DISABLE));
        m_nCursorID = IDC_VLINEUP_DISABLE;
      }
    }
    else
    {
      if(m_nCursorID != IDC_VLINEUP)
      {
        SetCursor(AfxGetApp()->LoadCursor(IDC_VLINEUP));
        m_nCursorID = IDC_VLINEUP;
      }
    }
    break;
  case SB_PAGEDOWN:      //Scroll one page down
    if(m_nCursorID != IDC_VPAGEDOWN)
    {
      SetCursor(AfxGetApp()->LoadCursor(IDC_VPAGEDOWN));
      m_nCursorID = IDC_VPAGEDOWN;
    }
    break;
  case SB_PAGEUP:        //Scroll one page up
    if(m_nCursorID != IDC_VPAGEUP)
    {
      SetCursor(AfxGetApp()->LoadCursor(IDC_VPAGEUP));
      m_nCursorID = IDC_VPAGEUP;
    }
    break;
  }
  BaseClass::OnVScroll(nSBCode, nPos, pScrollBar);
}

void CMyWnd::OnHScroll(UINT nSBCode, UINT nPos,
                       CScrollBar* pScrollBar)
{
  switch (nSBCode) {
  case SB_THUMBTRACK:    //Drag scroll box to specified position
    if(m_nCursorID != IDC_HTHUMBTRACK)
    {
      SetCursor(AfxGetApp()->LoadCursor(IDC_HTHUMBTRACK));
      m_nCursorID = IDC_HTHUMBTRACK;
    }
    break;
  case SB_LINEDOWN:      //Scroll one line down
    if(GetScrollPos(SB_HORZ) == GetScrollLimit(SB_HORZ))
    {
      if(m_nCursorID != IDC_HLINEDOWN_DISABLE)
      {
        SetCursor(AfxGetApp()->LoadCursor(IDC_HLINEDOWN_DISABLE));
        m_nCursorID = IDC_HLINEDOWN_DISABLE;
      }
    }
    else
    {
      if(m_nCursorID != IDC_HLINEDOWN)
      {
        SetCursor(AfxGetApp()->LoadCursor(IDC_HLINEDOWN));
        m_nCursorID = IDC_HLINEDOWN;
      }
    }
    break;
  case SB_LINEUP:        //Scroll one line up
    SCROLLINFO  info;
    info.cbSize = sizeof(SCROLLINFO);
    GetScrollInfo(SB_HORZ, &info);
    if(info.nPos == info.nMin)
    {
      if(m_nCursorID != IDC_HLINEUP_DISABLE)
      {
        SetCursor(AfxGetApp()->LoadCursor(IDC_HLINEUP_DISABLE));
        m_nCursorID = IDC_HLINEUP_DISABLE;
      }
    }
    else
    {
      if(m_nCursorID != IDC_HLINEUP)
      {
        SetCursor(AfxGetApp()->LoadCursor(IDC_HLINEUP));
        m_nCursorID = IDC_HLINEUP;
      }
    }
    break;
  case SB_PAGEDOWN:      //Scroll one page down
    if(m_nCursorID != IDC_HPAGEDOWN)
    {
      SetCursor(AfxGetApp()->LoadCursor(IDC_HPAGEDOWN));
      m_nCursorID = IDC_HPAGEDOWN;
    }
    break;
  case SB_PAGEUP:        //Scroll one page up
    if(m_nCursorID != IDC_HPAGEUP)
    {
      SetCursor(AfxGetApp()->LoadCursor(IDC_HPAGEUP));
      m_nCursorID = IDC_HPAGEUP;
    }
    break;
  }
  BaseClass::OnHScroll(nSBCode, nPos, pScrollBar);
}

Downloads

Download demo project - 37 Kb


This article was originally published on February 25th, 2003

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