HOWTO: How to Place Static Text Labels Over Columns in a List Box

   xpos = (avg_char_width * tab_stop_position) / 4.
				

   xpos = (avg_char_width * tab_stop_position + 2) / 4
				

1. Define a dialog template with a list box (m_listbox) and one or more static text labels (m_text1 and m_text2).
2. In the derived class for the dialog box, define a handler for OnInitDialog(). Modify the OnInitDialog to provide functionality similar to that provided by the following code sample.

Sample Code

BOOL CMyDlg::OnInitDialog()
{
    CDialog::OnInitDialog();

    // Set tabstops at 100 and 200 dialog units
    int tab_stop[2] = {100, 200};
    VERIFY(m_listbox.SetTabStops(2, tab_stop));

    m_listbox.AddString("String1\tString2\tString3");

    CDC *pDC = m_listbox.GetDC();

    // Get a handle to the font used in the list box
    CFont *pFont;
    pFont = m_listbox.GetFont();

    // Select the list box font into the temporary DC
    CFont *pFontOld = pDC->SelectObject(pFont);

    // Call GetTextExtentPoint to compute the string dimensions
    // NOTE: use GetTextExtentPoint32 in Win32 for better results
    CSize size;
    GetTextExtentPoint(pDC->GetSafeHdc(),
      "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz",
      52, &size);

    int avg_char_width = (size.cx/26 +1)/2;

    // Restore Original Font
    pDC->SelectObject(pFontOld);

    m_listbox.ReleaseDC(pDC);

    // Convert DLU to pixel positions
    int xPos1 = (tab_stop[0] * avg_char_width + 2)/4;
    int xPos2 = (tab_stop[1] * avg_char_width + 2)/4;

    // Only concerned about x right now, so y is set to 0
    CPoint mypt1(xPos1, 0);
    CPoint mypt2(xPos2, 0);

    // Convert the coordinates to be relative to the list box
    m_listbox.ClientToScreen(&mypt1);
    m_listbox.ClientToScreen(&mypt2);

    // Convert the screen coordinates back to coordinates that
    // are relative to the dialog box
    ScreenToClient(&mypt1);
    ScreenToClient(&mypt2);

    // Get the current position / width of the text labels
    CRect rect1,rect2;
    m_text1.GetWindowRect(&rect1);
    m_text2.GetWindowRect(&rect2);

    // Convert the rectangles to be relative to the dialog box
    ScreenToClient(&rect1);
    ScreenToClient(&rect2);

    // Move the text labels over the columns
    m_text1.MoveWindow(mypt1.x, rect1.top,
                       rect1.Width(),rect1.Height());
    m_text2.MoveWindow(mypt2.x, rect2.top,
                       rect2.Width(),rect2.Height());

    return TRUE;
}