Custom Draw items inside a ListView Control

If you do not want to go through the hassle implementing OwnerDraw list controls, where you got to code a bunch of stuff inside the DrawItem override, then you can use the CustomDraw handler. With version 4.70 of the Comctrl.dll, you can handle row data, but with the 4.72+ version of the Dll, you can handle cell data. Which opens a lot of possibilities.

Here I present some examples on how to use the CustomDraw message.

Note: Similar handling is also possible for the other common controls.

Add the following to your CListCtrl derived class header file:


afx_msg void OnCustomDraw(NMHDR* pNMHDR, LRESULT* pResult);

// add the following to your message map in the cpp file.
ON_NOTIFY_REFLECT(NM_CUSTOMDRAW, OnCustomDraw)

// add the following function to the cpp file.
// for specialized row handling.
// modify to suit.  (in this sample function, I color every alternate row).
void CListCtrlEx::OnCustomDraw(NMHDR* pNMHDR, LRESULT* pResult)
{
 //for this notification, the structure is actually a
 // NMLVCUSTOMDRAW that tells you what's going on with the custom
 // draw action. So, we'll need to cast the generic pNMHDR pointer.
 LPNMLVCUSTOMDRAW  lplvcd = (LPNMLVCUSTOMDRAW)pNMHDR;

 switch(lplvcd->nmcd.dwDrawStage)
 {
  case CDDS_PREPAINT:
   *pResult = CDRF_NOTIFYITEMDRAW;          // ask for item notifications.
  break;

  case CDDS_ITEMPREPAINT:
   *pResult = CDRF_DODEFAULT;

   int iRow = lplvcd->nmcd.dwItemSpec;
   if(iRow & 1)
   {
    lplvcd->clrTextBk = RGB(255, 0, 0);
    lplvcd->clrText = RGB(255, 255, 0);
    *pResult = CDRF_NEWFONT;
   }
  break;

  default:
   *pResult = CDRF_DODEFAULT;
 }
}

// add the following function to the cpp file.
// for specialized cell handling.
// modify to suit. (in this sample function, I color every alternate cell).
void CListCtrlEx::OnCustomDraw(NMHDR* pNMHDR, LRESULT* pResult)
{
 //for this notification, the structure is actually a
 // NMLVCUSTOMDRAW that tells you what's going on with the custom
 // draw action. So, we'll need to cast the generic pNMHDR pointer.
 LPNMLVCUSTOMDRAW  lplvcd = (LPNMLVCUSTOMDRAW)pNMHDR;

 switch(lplvcd->nmcd.dwDrawStage)
 {
  case CDDS_PREPAINT:
   *pResult = CDRF_NOTIFYSUBITEMDRAW;          // ask for subitem notifications.
  break;

  case CDDS_ITEMPREPAINT:
   *pResult = CDRF_NOTIFYSUBITEMDRAW;          // ask for subitem notifications.
  break;

  case CDDS_ITEMPREPAINT|CDDS_SUBITEM: // recd when CDRF_NOTIFYSUBITEMDRAW is returned in
  {                                    // response to CDDS_ITEMPREPAINT.
   *pResult = CDRF_DODEFAULT;

   int iCol = lplvcd->iSubItem;
   int iRow = lplvcd->nmcd.dwItemSpec;

   if((iRow & 1) && (iCol & 1))
   {
    lplvcd->clrTextBk = RGB(255, 0, 0);
    lplvcd->clrText = RGB(255, 255, 0);
    *pResult = CDRF_NEWFONT;
   }
  break;
  }

  default:// it wasn't a notification that was interesting to us.
   *pResult = CDRF_DODEFAULT;
  }
 }

// add the following function to the cpp file.
// for specialized cell handling.
// modify to suit.
// (in this sample function, I color every alternate cell,
// if the checkbox style is not present, otherwise, I color all checked rows).
void CListCtrlEx::OnCustomDraw(NMHDR* pNMHDR, LRESULT* pResult)
{
 //for this notification, the structure is actually a
 // NMLVCUSTOMDRAW that tells you what's going on with the custom
 // draw action. So, we'll need to cast the generic pNMHDR pointer.
 LPNMLVCUSTOMDRAW  lplvcd = (LPNMLVCUSTOMDRAW)pNMHDR;

 switch(lplvcd->nmcd.dwDrawStage)
 {
  case CDDS_PREPAINT:
   *pResult = CDRF_NOTIFYSUBITEMDRAW;          // ask for subitem notifications.
  break;

  case CDDS_ITEMPREPAINT:
   *pResult = CDRF_NOTIFYSUBITEMDRAW;          // ask for subitem notifications.

   if(GetExtendedStyle() & LVS_EX_CHECKBOXES)  // if we have a checkbox style,
   {                                           // forget about subitem notifications.
    *pResult = CDRF_DODEFAULT; 

    int iRow = lplvcd->nmcd.dwItemSpec;
    if(GetCheck(iRow))                      // highlight checked rows
    {
     lplvcd->clrTextBk = RGB(255, 0, 0);
     lplvcd->clrText = RGB(255, 255, 0);
     *pResult = CDRF_NEWFONT;
    }
   }
  break;

  case CDDS_ITEMPREPAINT|CDDS_SUBITEM: // recd when CDRF_NOTIFYSUBITEMDRAW is returned in
  {                                    // response to CDDS_ITEMPREPAINT.
   *pResult = CDRF_DODEFAULT;

   int iCol = lplvcd->iSubItem;
   int iRow = lplvcd->nmcd.dwItemSpec;

   if((iRow & 1) && (iCol & 1))
   {
    lplvcd->clrTextBk = RGB(255, 0, 0);
    lplvcd->clrText = RGB(255, 255, 0);
    *pResult = CDRF_NEWFONT;
   }
  break;
  }

  default:// it wasn't a notification that was interesting to us.
   *pResult = CDRF_DODEFAULT;
 }
}

// add the following function to the cpp file.
// for specialized cell handling.
// modify to suit.
// (in this sample function, I display the text centered).
void CListCtrlEx::OnCustomDraw(NMHDR* pNMHDR, LRESULT* pResult)
{
 //for this notification, the structure is actually a
 // NMLVCUSTOMDRAW that tells you what's going on with the custom
 // draw action. So, we'll need to cast the generic pNMHDR pointer.
 LPNMLVCUSTOMDRAW  lplvcd = (LPNMLVCUSTOMDRAW)pNMHDR;

 switch(lplvcd->nmcd.dwDrawStage)
 {
  case CDDS_PREPAINT:
   *pResult = CDRF_NOTIFYSUBITEMDRAW;          // ask for subitem notifications.
  break;

  case CDDS_ITEMPREPAINT:
   *pResult = CDRF_NOTIFYSUBITEMDRAW;
  break;

  case CDDS_ITEMPREPAINT|CDDS_SUBITEM:
  {
   int iCol = lplvcd->iSubItem;
   int iRow = lplvcd->nmcd.dwItemSpec;
   CString sItem = GetItemText(iRow, iCol);
   CRect rc;
   GetCellRect(iRow, iCol, LVIR_BOUNDS, rc);

   // get the device context.
   CDC *pDC= CDC::FromHandle(lplvcd->nmcd.hdc);

   // paint the text centered.
   pDC->DrawText(sItem , rc, DT_CENTER);

   *pResult= CDRF_SKIPDEFAULT;
   break;
  }

  default:// it wasn't a notification that was interesting to us.
   *pResult = CDRF_DODEFAULT;
 }
}
Where GetCellRect is defined as follows:

BOOL CListCtrlEx::GetCellRect(int iRow, int iCol, int nArea, CRect &rect)
{
 if(iCol)
  return GetSubItemRect(iRow, iCol, nArea, rect);

 if(GetColumnCount()== 1)
  return GetItemRect(iRow, rect, nArea);

 iCol = 1;
 CRect rCol1;
 if(!GetSubItemRect(iRow, iCol, nArea, rCol1))
  return FALSE;

 if(!GetItemRect(iRow, rect, nArea))
  return FALSE;

 rect.right = rCol1.left;

 return TRUE;
}

History



Comments

Leave a Comment
  • Your email address will not be published. All fields are required.

Top White Papers and Webcasts

  • With JRebel, developers get to see their code changes immediately, fine-tune their code with incremental changes, debug, explore and deploy their code with ease (both locally and remotely), and ultimately spend more time coding instead of waiting for the dreaded application redeploy to finish. Every time a developer tests a code change it takes minutes to build and deploy the application. JRebel keeps the app server running at all times, so testing is instantaneous and interactive.

  • It's time high-level executives and IT compliance officers recognize and acknowledge the danger of malicious insiders, an increased attack surface and the potential for breaches caused by employee error or negligence. See why there is extra emphasis on insider threats.

Most Popular Programming Stories

More for Developers

Latest Developer Headlines

RSS Feeds