Selection highlighting of entire row

When the list view control is in the report view, only the first column of the selected row is highlighted. To enable highlighting of the entire row, the list view control has to be owner drawn. That is, the onus of highlighting the row is on the programmer. Visual C++ already comes with an MFC sample that shows how to do this. The name of the sample is ROWLIST. The code given below was written after studying the sample code and fixes a few bugs present in the sample. One of the bug was that displaying state images messed up the text justification. Another bug was that if you resized the column to zero width ( to hide it ), the hidden columns content spilled over to the next column.

Step 1: Create the control with LVS_OWNERDRAWFIXED style

If you are using a CListView derived class then add the LVS_OWNERDRAWFIXED fixed style in the PreCreateWindow() function. Here's an example

BOOL CListViewEx::PreCreateWindow(CREATESTRUCT& cs)
{
	// default is report view and full row selection
	cs.style &= ~LVS_TYPEMASK;
	cs.style &= ~LVS_SHOWSELALWAYS;
	cs.style |= LVS_REPORT | LVS_OWNERDRAWFIXED;
	cs.style |= LVS_EDITLABELS;

	return(CListView::PreCreateWindow(cs));
}

Step 2: Add member variable and initialize it

Initialize m_nHighlight in the constructor to a value you feel should be the default. Since we are talking about full row selection it will probably be either HIGHLIGHT_ALLCOLUMNS or HIGHLIGHT_ROW.

public:
	enum EHighlight {HIGHLIGHT_NORMAL, HIGHLIGHT_ALLCOLUMNS, HIGHLIGHT_ROW};
protected:
	int  m_nHighlight;		// Indicate type of selection highlighting

Step 3: Override DrawItem()

The next segment of code determines if the item needs to be highlighted. The condition for highlighting an item is that the item should be drop-highlighted or it should be selected. By default the selection is shown only if the control has the focus or if the control has the LVS_SHOWSELALWAYS style. You may have noticed with non owner drawn controls that if an item is highlighted when the control does not have focus then the highlight color is different (usually gray). In our code below we do not make this differentiation but you can easily add it if you want.

The next significant step is the statement where we set a variable to twice the width of a space character. This value is used as an offset when we draw the text in the columns. This offset is used to give a white space margin on both ends of the main label and the subitem text.

The function then computes the highlight rectangle and sets up the device context and draws the highlight. We then draw the state image, the item image and the item label (e.i. text for column 1). Before we actually draw any of these we set the clip region for the device context so that all output is constrained within the first column. For item images, you'll notice that we use ILD_BLEND50 flag for selected items. This gives the effect that the image is also selected. If you don't want the image to look different for selected items then remove this flag. Also note that the item label is always drawn left justified. This is the default behaviour of the list view control so we mimic that.

The DrawText() function is used to draw the text for all the columns. The last argument to this function is a flag that tells the function how to draw the text. One flag of special interest to us is the DT_END_ELLIPSIS. This causes the DrawText() function to replace part of the given string with ellipses, if necessary, so that the result fits in the column bounds. This is again meant to mimic the default behaviour of the control.

We then restore the text color and text background color if the highlighting was for the first column only and then we draw the remainder of the column texts. For the sub-item text we make sure that it gets the text justification information from the column and uses it. We finally draw the focus rectangle and restore the device context.

void CMyListCtrl::DrawItem(LPDRAWITEMSTRUCT lpDrawItemStruct)
{
	CDC* pDC = CDC::FromHandle(lpDrawItemStruct->hDC);
	CRect rcItem(lpDrawItemStruct->rcItem);
	int nItem = lpDrawItemStruct->itemID;
	CImageList* pImageList;

	// Save dc state
	int nSavedDC = pDC->SaveDC();

	// Get item image and state info
	LV_ITEM lvi;
	lvi.mask = LVIF_IMAGE | LVIF_STATE;
	lvi.iItem = nItem;
	lvi.iSubItem = 0;
	lvi.stateMask = 0xFFFF;		// get all state flags
	GetItem(&lvi);

	// Should the item be highlighted
	BOOL bHighlight =((lvi.state & LVIS_DROPHILITED)
				|| ( (lvi.state & LVIS_SELECTED)
					&& ((GetFocus() == this)
						|| (GetStyle() & LVS_SHOWSELALWAYS)
						)
					)
				);


	// Get rectangles for drawing
	CRect rcBounds, rcLabel, rcIcon;
	GetItemRect(nItem, rcBounds, LVIR_BOUNDS);
	GetItemRect(nItem, rcLabel, LVIR_LABEL);
	GetItemRect(nItem, rcIcon, LVIR_ICON);
	CRect rcCol( rcBounds ); 


	CString sLabel = GetItemText( nItem, 0 );

	// Labels are offset by a certain amount  
	// This offset is related to the width of a space character
	int offset = pDC->GetTextExtent(_T(" "), 1 ).cx*2;

	CRect rcHighlight;
	CRect rcWnd;
	int nExt;
	switch( m_nHighlight )
	{
	case 0: 
		nExt = pDC->GetOutputTextExtent(sLabel).cx + offset;
		rcHighlight = rcLabel;
		if( rcLabel.left + nExt < rcLabel.right )
			rcHighlight.right = rcLabel.left + nExt;
		break;
	case 1:
		rcHighlight = rcBounds;
		rcHighlight.left = rcLabel.left;
		break;
	case 2:
		GetClientRect(&rcWnd);
		rcHighlight = rcBounds;
		rcHighlight.left = rcLabel.left;
		rcHighlight.right = rcWnd.right;
		break;
	default:
		rcHighlight = rcLabel;
	}

	// Draw the background color
	if( bHighlight )
	{
		pDC->SetTextColor(::GetSysColor(COLOR_HIGHLIGHTTEXT));
		pDC->SetBkColor(::GetSysColor(COLOR_HIGHLIGHT));

		pDC->FillRect(rcHighlight, &CBrush(::GetSysColor(COLOR_HIGHLIGHT)));
	}
	else
		pDC->FillRect(rcHighlight, &CBrush(::GetSysColor(COLOR_WINDOW)));

	

	// Set clip region
	rcCol.right = rcCol.left + GetColumnWidth(0);
	CRgn rgn;
	rgn.CreateRectRgnIndirect(&rcCol);
	pDC->SelectClipRgn(&rgn);
	rgn.DeleteObject();

	// Draw state icon
	if (lvi.state & LVIS_STATEIMAGEMASK)
	{
		int nImage = ((lvi.state & LVIS_STATEIMAGEMASK)>>12) - 1;
		pImageList = GetImageList(LVSIL_STATE);
		if (pImageList)
		{
			pImageList->Draw(pDC, nImage,
				CPoint(rcCol.left, rcCol.top), ILD_TRANSPARENT);
		}
	}
	
	// Draw normal and overlay icon
	pImageList = GetImageList(LVSIL_SMALL);
	if (pImageList)
	{
		UINT nOvlImageMask=lvi.state & LVIS_OVERLAYMASK;
		pImageList->Draw(pDC, lvi.iImage, 
			CPoint(rcIcon.left, rcIcon.top),
			(bHighlight?ILD_BLEND50:0) | ILD_TRANSPARENT | nOvlImageMask );
	}

	
	
	// Draw item label - Column 0
	rcLabel.left += offset/2;
	rcLabel.right -= offset;

	pDC->DrawText(sLabel,-1,rcLabel,DT_LEFT | DT_SINGLELINE | DT_NOPREFIX | DT_NOCLIP 
				| DT_VCENTER | DT_END_ELLIPSIS);


	// Draw labels for remaining columns
	LV_COLUMN lvc;
	lvc.mask = LVCF_FMT | LVCF_WIDTH;

	if( m_nHighlight == 0 )		// Highlight only first column
	{
		pDC->SetTextColor(::GetSysColor(COLOR_WINDOWTEXT));
		pDC->SetBkColor(::GetSysColor(COLOR_WINDOW));
	}
	
	rcBounds.right = rcHighlight.right > rcBounds.right ? rcHighlight.right :
							rcBounds.right;
	rgn.CreateRectRgnIndirect(&rcBounds);
	pDC->SelectClipRgn(&rgn);
				   
	for(int nColumn = 1; GetColumn(nColumn, &lvc); nColumn++)
	{
		rcCol.left = rcCol.right;
		rcCol.right += lvc.cx;

		// Draw the background if needed
		if( m_nHighlight == HIGHLIGHT_NORMAL )
			pDC->FillRect(rcCol, &CBrush(::GetSysColor(COLOR_WINDOW)));

		sLabel = GetItemText(nItem, nColumn);
		if (sLabel.GetLength() == 0)
			continue;

		// Get the text justification
		UINT nJustify = DT_LEFT;
		switch(lvc.fmt & LVCFMT_JUSTIFYMASK)
		{
		case LVCFMT_RIGHT:
			nJustify = DT_RIGHT;
			break;
		case LVCFMT_CENTER:
			nJustify = DT_CENTER;
			break;
		default:
			break;
		}

		rcLabel = rcCol;
		rcLabel.left += offset;
		rcLabel.right -= offset;

		pDC->DrawText(sLabel, -1, rcLabel, nJustify | DT_SINGLELINE | 
					DT_NOPREFIX | DT_VCENTER | DT_END_ELLIPSIS);
	}

	// Draw focus rectangle if item has focus
	if (lvi.state & LVIS_FOCUSED && (GetFocus() == this))
		pDC->DrawFocusRect(rcHighlight);

	
	// Restore dc
	pDC->RestoreDC( nSavedDC );
}

Step 4: Define RepaintSelectedItems() helper function

void CMyListCtrl::RepaintSelectedItems()
{
	CRect rcBounds, rcLabel;

	// Invalidate focused item so it can repaint 
	int nItem = GetNextItem(-1, LVNI_FOCUSED);

	if(nItem != -1)
	{
		GetItemRect(nItem, rcBounds, LVIR_BOUNDS);
		GetItemRect(nItem, rcLabel, LVIR_LABEL);
		rcBounds.left = rcLabel.left;

		InvalidateRect(rcBounds, FALSE);
	}

	// Invalidate selected items depending on LVS_SHOWSELALWAYS
	if(!(GetStyle() & LVS_SHOWSELALWAYS))
	{
		for(nItem = GetNextItem(-1, LVNI_SELECTED);
			nItem != -1; nItem = GetNextItem(nItem, LVNI_SELECTED))
		{
			GetItemRect(nItem, rcBounds, LVIR_BOUNDS);
			GetItemRect(nItem, rcLabel, LVIR_LABEL);
			rcBounds.left = rcLabel.left;

			InvalidateRect(rcBounds, FALSE);
		}
	}

	UpdateWindow();
}

Step 5: Add code to OnPaint() to invalidate entire row

void CMyListCtrl::OnPaint() 
{
	// in full row select mode, we need to extend the clipping region
	// so we can paint a selection all the way to the right
	if (m_nHighlight == HIGHLIGHT_ROW &&
		(GetStyle() & LVS_TYPEMASK) == LVS_REPORT )
	{
		CRect rcBounds;
		GetItemRect(0, rcBounds, LVIR_BOUNDS);

		CRect rcClient;
		GetClientRect(&rcClient);
		if(rcBounds.right < rcClient.right)
		{
			CPaintDC dc(this);

			CRect rcClip;
			dc.GetClipBox(rcClip);

			rcClip.left = min(rcBounds.right-1, rcClip.left);
			rcClip.right = rcClient.right;

			InvalidateRect(rcClip, FALSE);
		}
	}

	CListCtrl::OnPaint();
}

Step 6: Add handlers for WM_KILLFOCUS and WM_SETFOCUS

void CMyListCtrl::OnKillFocus(CWnd* pNewWnd) 
{
	CListCtrl::OnKillFocus(pNewWnd);

	// check if we are losing focus to label edit box
	if(pNewWnd != NULL && pNewWnd->GetParent() == this)
		return;

	// repaint items that should change appearance
	if((GetStyle() & LVS_TYPEMASK) == LVS_REPORT)
		RepaintSelectedItems();
}

void CMyListCtrl::OnSetFocus(CWnd* pOldWnd) 
{
	CListCtrl::OnSetFocus(pOldWnd);
	
	// check if we are getting focus from label edit box
	if(pOldWnd!=NULL && pOldWnd->GetParent()==this)
		return;

	// repaint items that should change appearance
	if((GetStyle() & LVS_TYPEMASK)==LVS_REPORT)
		RepaintSelectedItems();
}

Step 7: Add helper function to change selection mode

int CMyListCtrl::SetHighlightType(EHighlight hilite)
{
	int oldhilite = m_nHighlight;
	if( hilite <= HIGHLIGHT_ROW )
	{
		m_nHighlight = hilite;
		Invalidate();
	}
	return oldhilite;
}