Horizontal and Vertical Scrollbar

[timberwolf]

I have created a dialog box with a list box in the resource.Under property style I have checked the vertical and horizontal scroll. When I execute the program andthe dialog box is displayed the list box shows the vertical scroll bar and it does work. Butit does not show thehorizontalscrollbar.

How would I make display both working vertical and horizontal scrollbar?

Any help is appriciated.

thanks

[Jugoslav_Dujic]

This is (broken) by design. List boxes do not display horizontal scrollbar unless you tell them explicitly what's the length of the (longest) item, in pixels.

LB_SETHORIZONTALEXTENT message sets the length of scrollbar thumb and shows it if necessary. As any Windows message used with DFLOGM, it will work only when called from a dialog callback. In addition, you have to select the text into a DC and then measure it in pixels in order to obtain the length. Here you are (untested):

Code:

Subroutine SetHorzScrollbar(Dlg, idListBox)

use Dflogm
use Dfwin

implicit none

type(Dialog)::         Dlg
integer, intent(in)::  idListBox

integer::              hDC, b, hFont, nItems, i, hOldFont, maxLen
type(T_SIZE)::         SZ
character(200)::       sItem

hFont = DlgSendCtrlMessage(Dlg, idListBox, WM_GETFONT, 0, 0)
nItems = DlgSendCtrlMessage(Dlg, idListBox, LB_GETCOUNT, 0, 0)
hDC = GetDC(GetDlgItem(Dlg%hWnd, idListBox))
hOldFont = SelectObject(hDC, hFont)

maxLen = 0
do i = 0, nItems-1
  !Get the i-th item
  b = DlgSendCtrlMessage(Dlg, idListBox, LB_GETTEXT, i, LOC(sItem))
  !Measure the text length in pixels
  b = GetTextExtentPoint32(hDC, sItem, index(sItem,char(0)-1), SZ)
  maxLen = max(maxLen, SZ%cx)
end do
b = DlgSendCtrlMessage(Dlg, idListBox, LB_SETHORIZONTALEXTENT, maxLen+5, 0)

b = SelectObject(hDC, hOldFont)

b = ReleaseDC(GetDlgItem(Dlg%hWnd), idListBox)

end subroutine SetHorzScrollbar

If you fill in the list box on startup, you should define a startup (DLG_INIT callback) and call the subroutine above from there. If you change the list box' contents dynamically, you have to call the subroutine after every change (or optimize it a little so that you don't iterate through entire list every time).

Jugoslav

Message Edited by JugoslavDujic on 08-27-2004 09:44 AM