Preventing ListView Column Resizing?

[George Bleck]

I'm pretty excited, I actually got the listview control to work in my program without any reference to the BBS for help (yes it's the simple things that make me happy).

Of course, as Murphy would have it I have hit a stumbling block.

How do you prevent the columns from being resized?

It looks like you can intercept a header notification called HDN_BEGINTRACK and I'm pretty sure the listview control is comprised of that sub-control. Does that mean I need to sub-class?


------------------

[George Bleck]

I think I found the answer on the web...

But I'm still not sure of the sub-classing. I unfortunately am not at my desk at work to test it, does anyone know for sure if you need/don't need to sub-class?

BTW, found a good site about listview controls..

http://zeus.eed.usv.ro/misc/doc/prog...tview_toc.html

------------------
George W. Bleck
Senior System Engineer
KeySpan Corporation

[Jules Marchildon]

George,

A small tip, anytime you have a Notification message, they are
always sent to the Parent window, so you don't have to subclass the
control in this case.

An example for just a plain header control. This should give you enough
info to get you started on the ListView.

'---
%ID_HEADCONTROL        = 500   
 
'---
local hdnptr      as HD_NOTIFY PTR
local hdiptr      as HD_ITEM   PTR
local hditem      as HD_ITEM     
local lo          as HD_LAYOUT  
'---
 
 ...
 
'---
    CASE %WM_NOTIFY
 
     select case lowrd(wParam)
 
       case %ID_HEADCONTROL
             hdnptr = lParam
             hdiptr = @hdnptr.pitem
 
         select case @hdnptr.hdr.code
 
               case %HDN_ENDTRACK
 
                     If (@hdiptr.cxy < %MINWIDTH)  THEN
                         @hdiptr.cxy = %MINWIDTH
                         Columns(@hdnptr.iItem) = %MINWIDTH
                     Else
                         Columns(@hdnptr.iItem) = @hdiptr.cxy
                         Call GetClientRect(ghWndMain,rc)
                         rc.ntop = HeaderHeight
                         Call InvalidateRect(ghWndMain,rc,%TRUE)
                         'UpdateWindow ghWndMain
                     End if
 
                     'Function = 0
                     'Exit Select
 
               case %HDN_TRACK
 
                     Call GetClientRect(ghWndMain,rc)
 
                        If(@hdiptr.cxy < %MINWIDTH) THEN
                           @hdiptr.cxy = %MINWIDTH
                           Columns(@hdnptr.iItem) = %MINWIDTH
 
                        Else
                           Columns(@hdnptr.iItem) = @hdiptr.cxy
                           rc.ntop = HeaderHeight
                           'Call InvalidateRect(ghWndMain,rc,%TRUE)
                           'UpdateWindow ghWndMain
                        End If
 
                    'Function = 0
                    'Exit Select
 
               case %HDN_ITEMCLICK
 
                     hditem.mask = %HDI_WIDTH
                     Call SendMessage(ghHeadWnd, %HDM_GETITEM, @hdnptr.iItem, VARPTR(hditem))
                     hditem.cxy = %DEFWIDTH
                     Columns(@hdnptr.iItem) = %DEFWIDTH
                     Call SendMessage(ghHeadWnd, %HDM_SETITEM, @hdnptr.iItem, VARPTR(hditem))
                     Call GetClientRect(ghWndMain,rc)
                     rc.ntop = HeaderHeight
                     Call InvalidateRect(ghWndMain,rc,%TRUE)
                     UpdateWindow ghWndMain
 
                     'Function =0
                     'Exit Select
 
               case %HDN_ITEMDBLCLICK
 
                     hditem.mask = %HDI_WIDTH
                     Call SendMessage(ghHeadWnd, %HDM_GETITEM, @hdnptr.iItem, VARPTR(hditem))
                     hditem.cxy = hditem.cxy + hditem.cxy
                        If (hditem.cxy > %MAXWIDTH) THEN
                            hditem.cxy = %MAXWIDTH
                        End If
 
                     Columns(@hdnptr.iItem) = hditem.cxy
                     Call SendMessage(ghHeadWnd, %HDM_SETITEM, @hdnptr.iItem, VARPTR(hditem))
                     Call GetClientRect(ghWndMain,rc)
                     rc.ntop = HeaderHeight
                     Call InvalidateRect(ghWndMain,rc,%TRUE)
                     UpdateWindow ghWndMain
 
                     'Function = 0
                     'Exit Select
 
         End Select
 
     End Select

HTH
Regards, Jules




[This message has been edited by Jules Marchildon (edited September 05, 2000).]