Simplified Subitem Editing

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Environment: VC6 SP5

This article suggests a way to subclass the listviews edit control, but unlike the article "Editing listview Subitems Using LVM_GETEDITCONTROL," it uses a much simpler and hopefully better method. Give it a try!

1. Vars

   public:
     CSubEdit m_editWnd;
     int m_item;
     int m_subitem;
   
   CSubeditListView::CSubeditListView()
   {
     m_subitem = 0;
   }
   

2. Detect subitem mouse clicks

   void CSubeditListView::OnLButtonDown(UINT nFlags, CPoint point)
   {
     LVHITTESTINFO  lvhit;
     lvhit.pt = point;
     int item = GetListCtrl().SubItemHitTest(&lvhit);
   
     //if (over a subitem)
     if (item != -1 && lvhit.iSubItem && (lvhit.flags & 
                       LVHT_ONITEM ))
       {
       //mouse click outside the editbox in an already
       //editing cell cancels editing
       if (m_subitem == lvhit.iSubItem && item == m_item)
         {
         CListView::OnLButtonDown(nFlags, point);
         }
       else
         {
         CListView::OnLButtonDown(nFlags, point);
   
         m_subitem = lvhit.iSubItem;
         m_item = item;
         GetListCtrl().EditLabel(item);
         }
   
       }
     else
       CListView::OnLButtonDown(nFlags, point);
   }
   

3. Handle OnBeginLabelEdit

   void CSubeditListView::OnBeginLabelEdit(NMHDR* pNMHDR,
       LRESULT* pResult)
   {
     LV_DISPINFO* pDispInfo = (LV_DISPINFO*)pNMHDR;
   
     //if (subitem selected for editing)
     if (m_subitem)
       {
       ASSERT(m_item == pDispInfo->item.iItem);
   
       CRect  subrect;
       GetListCtrl().GetSubItemRect( pDispInfo->item.iItem,
                                     m_subitem,
           LVIR_BOUNDS , subrect );
   
       //get edit control and subclass
       HWND hWnd=(HWND)SendMessage(LVM_GETEDITCONTROL);
       ASSERT(hWnd!=NULL);
       VERIFY(m_editWnd.SubclassWindow(hWnd));
   
       //move edit control text 1 pixel to the right of org label,
       //as Windows does it...
       m_editWnd.m_x=subrect.left + 6; 
       m_editWnd.SetWindowText(GetListCtrl().GetItemText
           (pDispInfo->item.iItem,m_subitem));
   
       //hide subitem text so it don't show if we delete some
       //text in the edit control
       //OnPaint handles other issues also regarding this
       CRect  rect;
       GetListCtrl().GetSubItemRect(pDispInfo->item.iItem,m_subitem,
           LVIR_LABEL ,rect);
       CDC* hDc = GetDC();
       hDc->FillRect(rect,&CBrush(::GetSysColor(COLOR_WINDOW)));
       ReleaseDC(hDc);
   
       }
   
     //return: editing permitted
     *pResult = 0;
   
   }
   

4. Positioning the editcontrol

   void CSubEdit::OnWindowPosChanging(WINDOWPOS FAR* lpwndpos)
   {
     lpwndpos->x=m_x;
   
     CEdit::OnWindowPosChanging(lpwndpos);
   }
   

5. Handle painting

   void CSubeditListView::OnPaint()
   {
     //if (subitem editing)
     if (m_subitem)
       {
   
       CRect  rect;
       CRect  editrect;
   
       GetListCtrl().GetSubItemRect(m_item,m_subitem,LVIR_LABEL,
                                    rect);
   
       m_editWnd.GetWindowRect(editrect);
       ScreenToClient(editrect);
   
       //block text redraw of the subitems text (underneath the
       //editcontrol)
       //if we didn't do this and deleted some text in the edit
       //control, the subitems original label would show
       if (editrect.right < rect.right)
         {
         rect.left = editrect.right ;
         ValidateRect(rect);
         }
   
       //block filling redraw of leftmost item (caused by FillRect)
       GetListCtrl().GetItemRect(m_item,rect,LVIR_LABEL );
       ValidateRect(rect);
       }
   
     CListView::OnPaint();
   }
   

6. Handle resizing

   void CSubeditListView::OnSize(UINT nType, int cx, int cy)
   {
     //stop editing if resizing
     if( GetFocus() != this ) SetFocus();
   
     CListView::OnSize(nType, cx, cy);
   
   }
   

7. Handle OnEndLabelEdit

   void CSubeditListView::OnEndLabelEdit(NMHDR* pNMHDR,
                                         LRESULT* pResult)
   {
     LV_DISPINFO *plvDispInfo = (LV_DISPINFO *)pNMHDR;
     LV_ITEM  *plvItem = &plvDispInfo->item;
   
     //if (end of sub-editing) do cleanup
     if (m_subitem)
       {
       //plvItem->pszText is NULL if editing canceled
       if (plvItem->pszText != NULL )
         GetListCtrl().SetItemText(plvItem->iItem,m_subitem,
             plvItem->pszText);
   
       VERIFY(m_editWnd.UnsubclassWindow()!=NULL);
   
       m_subitem = 0;
       //always revert to org label (Windows thinks we are editing
       //the leftmost item)
       *pResult = 0;
       }
     else
       //return: update label on leftmost item
       *pResult = 1;
   
   }
   

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