void CResizableComboBox::PreSubclassWindow()
{
ASSERT(GetStyle() & CBS_NOINTEGRALHEIGHT);
InitHorizontalExtent();
GetDroppedControlRect(&m_rectDropDown);
::MapWindowPoints(NULL, GetSafeHwnd(),
(LPPOINT)&m_rectDropDown, 2);
CComboBox::PreSubclassWindow();
}
//------------------------------------------------------------------------
//! CBN_DROPDOWN message handler called when the CComboBox control
//! is expanded into a dropdown list. Used to restrict the width of
//! the dropdown list to the max width.
//------------------------------------------------------------------------
void CGridEditorComboBox::OnDropDown()
{
int itemHeight = GetItemHeight(-1);
int nNumEntries = GetCount();
// Resize combobox according to actual element count
int visibleItemCount = m_MaxHeightItems < nNumEntries ? m_MaxHeightItems : nNumEntries; // min(m_MaxHeightItems, nNumEntries);
CRect rectExpanded;
GetClientRect(rectExpanded);
rectExpanded.bottom += visibleItemCount * GetItemHeight(0);
rectExpanded.bottom += GetSystemMetrics(SM_CYEDGE) * 2; // top & bottom edges
SetWindowPos(NULL, // not relative to any other windows
0, 0, // TopLeft corner doesn't change
rectExpanded.Width(), rectExpanded.Height(), // existing width, new height
SWP_NOMOVE | SWP_NOZORDER // don't move box or change z-ordering.
);
// Resize combo-box width to fit contents
int nMaxItemWidth = 0;
CString str;
// Find max-width of the elements
CDC* pDC = GetDC();
CFont* pFont = GetFont();
CFont* pOldFont = pDC->SelectObject(pFont);
for (int i = 0; i < nNumEntries; i++)
{
GetLBText(i, str);
int nLength = pDC->GetTextExtent(str).cx;
nMaxItemWidth = nMaxItemWidth > nLength ? nMaxItemWidth : nLength; // max(nMaxItemWidth, nLength);
if (nMaxItemWidth > m_MaxWidthPixels)
{
nMaxItemWidth = m_MaxWidthPixels;
break;
}
}
// Check if there are so many elements that we need space for a vertical scrollbar
CRect rect;
GetDroppedControlRect(&rect);
if (rect.Height() <= nNumEntries*GetItemHeight(0))
nMaxItemWidth +=::GetSystemMetrics(SM_CXVSCROLL);
// Add margin space to the calculations
nMaxItemWidth += pDC->GetTextExtent(_T("0")).cx;
pDC->SelectObject(pOldFont);
ReleaseDC(pDC);
SetDroppedWidth(nMaxItemWidth);
SetItemHeight(-1, itemHeight);
}
int COXMultiComboBox::AdjustToFitSize()
{
int nResult;
if(m_bFitToSize)
{
int nTotalWidth=GetTotalWidth()+2*GetSystemMetrics(SM_CXBORDER);
int nTotalHeight=GetTotalHeight();
int nBorderHeight=GetSystemMetrics(SM_CYBORDER);
int nScrollbarHeight=GetSystemMetrics(SM_CYHSCROLL);
CRect rcDrop;
GetDroppedControlRect(&rcDrop);
if((nTotalHeight > rcDrop.Height()-2*nBorderHeight) ||
((nTotalWidth > rcDrop.Width()) &&
(nTotalHeight > rcDrop.Height()-nScrollbarHeight-2*nBorderHeight)))
{
nTotalWidth+=::GetSystemMetrics(SM_CXVSCROLL);
}
int nScreenWidth=::GetSystemMetrics(SM_CXSCREEN);
nTotalWidth=nTotalWidth>nScreenWidth ? nScreenWidth : nTotalWidth;
nResult=SetDroppedWidth(nTotalWidth);
}
else
nResult=SetDroppedWidth(1);
if(nResult!=CB_ERR)
{
// ... To indicate that the scrollbars has to be re-adjusted
m_fSizeChanged = TRUE;
// Redraws the listbox
if(::IsWindow(m_ComboLBox.m_hWnd))
{
m_ComboLBox.RedrawWindow(NULL,NULL,
RDW_ERASE|RDW_INVALIDATE|RDW_ERASENOW|RDW_UPDATENOW|RDW_FRAME);
}
}
return nResult;
}
// This message is handle to get the HWND of the listbox of the combobox
// as there is no otherway to get it(refer to Q65881, Q131845 in Knowledge Base)
// The listbox handle is needed to set the scrollbar to it if needed, and to
// handle its WM_HSCROLL message.
HBRUSH COXMultiComboBox::OnCtlColor(CDC* pDC, CWnd* pWnd, UINT nCtlColor)
// --- In : pDC : device context (See standard help for detaled info)
// pWnd : Pointer Cwnd obejct of the window whose background
// has to be painted.
// nCtlColor : Type of the control
// --- Out :
// --- Returns : Brush to supply to paint the background
// --- Effect : The listbox's HWND is got and sunclassed to COXComboLBox
// window object. The listbox style is modified to
// have WS_HSCROLL. The horizontal extent of the listbox is
// set and scrollbars are shown are hided depending on the
// width and height. Scroll range for horizantal scrollbar
// is set and also m_NumCharsPerPage is set.
{
HBRUSH hbr = CComboBox::OnCtlColor(pDC, pWnd, nCtlColor);
// Handle only if the type of control is Listbox only
if ((nCtlColor == CTLCOLOR_LISTBOX) && m_fSizeChanged)
{
// ... To stop this code run unneccessorily
m_fSizeChanged = FALSE;
if(m_ComboLBox.GetSafeHwnd()==NULL)
{
m_ComboLBox.SubclassWindow(pWnd->GetSafeHwnd());
m_ComboLBox.ModifyStyle(0,WS_HSCROLL);
TEXTMETRIC tm;
GetTextMetrics(pDC->m_hDC,&tm);
m_nLineWidth = tm.tmAveCharWidth;
}
int nTotalWidth = GetTotalWidth();
// ... Sets horizontal extent to total width
m_ComboLBox.SetHorizontalExtent(nTotalWidth);
CRect rcDrop;
GetDroppedControlRect(&rcDrop);
int iTotalItemHeight = 0;
for (int i = 0; i < m_ComboLBox.GetCount(); i++)
iTotalItemHeight += m_ComboLBox.GetItemHeight(i);
if (rcDrop.Height() < iTotalItemHeight || m_bFitToSize)
m_ComboLBox.AdjustHScroll();
if(GetStyle()&CBS_DROPDOWN)
{
CRect rcWnd;
m_ComboLBox.GetWindowRect(&rcWnd);
m_ComboLBox.MoveWindow(&rcWnd,TRUE);
}
if(m_ComboLBox.m_fHorzScrollVisible)
{
CRect rcClient;
m_ComboLBox.GetClientRect(&rcClient);
m_nPageWidth = rcClient.Width();
// setting sroll info
SCROLLINFO si;
si.cbSize = sizeof(si);
si.nPos = 0;
si.nMin = 0;
si.nMax = nTotalWidth;
si.nPage = m_nPageWidth;
si.fMask = SIF_PAGE | SIF_RANGE | SIF_POS ;
m_ComboLBox.SetScrollInfo(SB_HORZ,&si,TRUE);
m_ComboLBox.SendMessage(WM_HSCROLL,SB_TOP,0L);
}
m_ComboLBox.RedrawWindow(NULL,NULL,RDW_INVALIDATE|RDW_FRAME);
}
return hbr;
}