Owner Drawn Combo

Hiya

I have been looking at the following link to create an owner drawn combo:

http://msdn.microsoft.com/en-us/library/y5hb5f9t(VS.71).aspx

The problem is that when I reach ASSERT(lpszText != NULL); the code trips up!

I am using a standard combo with HasStrings set to TRUE. I am using Visual Studio 2008 with Unicode enabled.

Can anybody help?

John

void CMyComboBox::DrawItem(LPDRAWITEMSTRUCT lpDrawItemStruct) 
{
   ASSERT(lpDrawItemStruct->CtlType == ODT_COMBOBOX);
   LPCTSTR lpszText = (LPCTSTR) lpDrawItemStruct->itemData;
   ASSERT(lpszText != NULL);
   CDC dc;
 
   dc.Attach(lpDrawItemStruct->hDC);
 
   // Save these value to restore them when done drawing.
   COLORREF crOldTextColor = dc.GetTextColor();
   COLORREF crOldBkColor = dc.GetBkColor();
 
   // If this item is selected, set the background color 
   // and the text color to appropriate values. Erase
   // the rect by filling it with the background color.
   if ((lpDrawItemStruct->itemAction | ODA_SELECT) &&
      (lpDrawItemStruct->itemState  & ODS_SELECTED))
   {
      dc.SetTextColor(::GetSysColor(COLOR_HIGHLIGHTTEXT));
      dc.SetBkColor(::GetSysColor(COLOR_HIGHLIGHT));
      dc.FillSolidRect(&lpDrawItemStruct->rcItem, ::GetSysColor(COLOR_HIGHLIGHT));
   }
   else
      dc.FillSolidRect(&lpDrawItemStruct->rcItem, crOldBkColor);
 
   // Draw the text.
   dc.DrawText(
      lpszText,
      strlen(lpszText),
      &lpDrawItemStruct->rcItem,
      DT_CENTER|DT_SINGLELINE|DT_VCENTER);
 
   // Reset the background color and the text color back to their
   // original values.
   dc.SetTextColor(crOldTextColor);
   dc.SetBkColor(crOldBkColor);
 
   dc.Detach();
}

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