HOWTO: Change Icon or Bitmap of CListCtrl Item When Selected

• The Microsoft Foundation Classes (MFC), included with:
  • Microsoft Visual C++, 32-bit Editions, versions 4.0, 5.0, 6.0

SUMMARY

This article shows how to change the icon or bitmap of a CListCtrl item when it is selected.

MORE INFORMATION

When you initialize the CListCtrl by calling CListCtrl::InsertItem(), you can pass in a value of I_IMAGECALLBACK for the index of the image. This means that the system expects you to fill in the image index when you get an LVN_GETDISPINFO notification. Inside of the handler for LVN_GETDISPINFO, you can check if the item is selected and set the appropriate image index.

Sample Code

   BEGIN_MESSAGE_MAP(CTestView, CView)
      //{{AFX_MSG_MAP(CTestView)
      ON_WM_CREATE()
      //}}AFX_MSG_MAP
      ON_NOTIFY (LVN_GETDISPINFO, IDI_LIST, OnGetDispInfo)
   END_MESSAGE_MAP()

   int CTestView::OnCreate(LPCREATESTRUCT lpCreateStruct)
   {
      if (CView::OnCreate(lpCreateStruct) == -1)
         return -1;

      // m_pImage is a CTestView's member variable of type CImageList*
      // create the CImageList with 16x15 images
      m_pImage = new CImageList();
      VERIFY (m_pImage->Create (16, 15, TRUE, 0, 1));
      CBitmap bm;
      // IDR_MAINFRAME is the toolbar bitmap in a default AppWizard
      // project.
      bm.LoadBitmap (IDR_MAINFRAME);
      // This will automatically parse the bitmap into nine images.
      m_pImage->Add (&bm, RGB (192, 192, 192));

      // m_pList is  CTestView's member variable of type CListCtrl*
      // create the CListCtrl.
      m_pList = new CListCtrl();
      VERIFY (m_pList->Create (WS_VISIBLE | WS_CHILD | LVS_REPORT |
          LVS_EDITLABELS, CRect (0, 0, 400, 400), this, IDI_LIST));
      // Create column.
      m_pList->InsertColumn (0, "Button Number", LVCFMT_LEFT, 100);
      // Associate CImageList with CListCtrl.
      m_pList->SetImageList (m_pImage, LVSIL_SMALL);

      char szTemp[10];
      for (int iCntr = 0; iCntr < 9; iCntr++)
      {
         wsprintf (szTemp, "%d", iCntr);
         m_pList->InsertItem (LVIF_IMAGE | LVIF_TEXT,
            iCntr, szTemp, 0, 0, I_IMAGECALLBACK, 0L);
      }
      return 0;
   }

   void CTestView::OnGetDispInfo (NMHDR* pnmhdr, LRESULT* pResult)
   {
      LV_DISPINFO* pdi = (LV_DISPINFO *) pnmhdr;

      // Fill in the LV_ITEM structure with the image info.
      // When an item is selected, the image is set to the first
      // image (the new bitmap on the toolbar).
      // When it is not selected, the image index is equal to the
      // item number (that is, 0=new, 1=open, 2=save, and so on.)
      if (LVIS_SELECTED == m_pList->GetItemState (pdi->item.iItem,
                         LVIS_SELECTED))
         pdi->item.iImage = 0;
      else
         pdi->item.iImage = pdi->item.iItem;
   }

   CTestView::~CTestView()
   {
      // Clean up.
      delete m_pImage;
      delete m_pList;
   } 

Keywords : kbcode kbprg kbMFC KbUIDesign kbVC kbVC400 kbVC500 kbVC600
Version : 4.0 5.0
Platform : NT WINDOWS
Issue type : kbhowto