创建CListCtrl中的排序小图标

创建CListCtrl中的排序小图标

for(int i = 0; i < GetHeaderCtrl()->GetItemCount(); ++i)
  {
   HDITEM hditem = {0};
   hditem.mask = HDI_BITMAP | HDI_FORMAT;
   VERIFY( GetHeaderCtrl()->GetItem( i, &hditem ) );
   if (hditem.fmt & HDF_BITMAP && hditem.fmt & HDF_BITMAP_ON_RIGHT)
   {
    if (hditem.hbm)
    {
     VERIFY( DeleteObject(hditem.hbm) );
     hditem.hbm = NULL;
    }
    hditem.fmt &= ~(HDF_BITMAP|HDF_BITMAP_ON_RIGHT);
    VERIFY( CListCtrl::GetHeaderCtrl()->SetItem( i, &hditem ) );
   }
   if (i == nCol)
   {
    hditem.fmt |= HDF_BITMAP|HDF_BITMAP_ON_RIGHT;
    //UINT bitmapID = m_Ascending ? IDB_DOWNARROW : IDB_UPARROW;
    //hditem.hbm = (HBITMAP)LoadImage(GetModuleHandle(NULL), MAKEINTRESOURCE(bitmapID), IMAGE_BITMAP, 0,0, LR_LOADMAP3DCOLORS);
    hditem.hbm = CreateSortBitmap(bAscending);
    VERIFY( hditem.hbm!=NULL );
    VERIFY( CListCtrl::GetHeaderCtrl()->SetItem( i, &hditem ) );
   }

HBITMAP CreateSortBitmap(bool bAscending)
 {
  // Aquire the Display DC
  CDC* pDC = CDC::FromHandle(::GetDC(::GetDesktopWindow()));
  //create a memory dc
  CDC memDC;
  memDC.CreateCompatibleDC(pDC);

  //Create a memory bitmap
  CBitmap newbmp;
  CRect iconRect(0, 0, 16, 16);
  newbmp.CreateCompatibleBitmap(pDC, iconRect.Height(), iconRect.Width());

  //create a black brush
  CBrush brush;
  brush.CreateSolidBrush(RGB(0, 0, 0));

  //select the bitmap in the memory dc
  CBitmap *pOldBitmap = memDC.SelectObject(&newbmp);

  //make the bitmap white to begin with
  memDC.FillSolidRect(iconRect.top,iconRect.left,iconRect.bottom,iconRect.right,::GetSysColor(COLOR_3DFACE));

  //draw a rectangle using the brush
  CBrush *pOldBrush = memDC.SelectObject(&brush);
  if (bAscending)
  {
   // Arrow pointing up
   CPoint Pt[3];
   Pt[0] = CPoint(7,  5); // Top
   Pt[1] = CPoint(4,  8); // Left
   Pt[2] = CPoint(10,  8); // Right
   memDC.Polygon(Pt, 3);
  }
  else
  {
   // Arrow pointing down
   CPoint Pt[3];
   Pt[0] = CPoint(10, 6); // Right
   Pt[1] = CPoint(4, 6); // Left
   Pt[2] = CPoint(7, 9); // Bottom
   memDC.Polygon(Pt, 3);
  }
  memDC.SelectObject(pOldBrush);

  //select old bitmap back into the memory dc
  memDC.SelectObject(pOldBitmap);

  return (HBITMAP)newbmp.Detach();
 }