OpenEuphoria

2. Re: [win32lib] subclassing Combo's EditText

• Posted by Derek Parnell <ddparnell at bigpond.com> Jul 13, 2002
• 468 views

Martin,
win32lib has already done this for you. To get the id of the editbox
belonging to a combo you can do something like this...

   sequence kids
   integer edid

   kids = findChildren(mycombo)
   for i = 1 to length(kids) do
       if kids[i][2] = EditText then
          edid = edid[i][1]
          exit
       end if
   end for

Another method is this...

   edid = subClassControl( {EditText,id},
                 w32Func(xGetWindow,{ geHandle(id), GW_CHILD}))

However, the reason that ChildWindowFromPoint didn't work is that definition
of it in win32lib is wrong.
The Microsoft C header is ...

HWND ChildWindowFromPoint(
  HWND hWndParent,  // handle to parent window
  POINT Point       // structure with point coordinates
);

which looks like it has two parameters. However, the second parameter is a
POINT structure; not a pointer to the structure, but the structure itself.
The POINT structure is two longs. So then the proper win32lib definition
should be ...

 ChildWindowFromPoint = registerw32Function( user32,
"ChildWindowFromPoint",{ C_LONG, C_LONG, C_LONG }, C_LONG ),

Which means that a third method is this...

  edid = getId(w32Func(ChildWindowFromPoint, {getHandle(pComboBox), 1,1}))

This last one works because win32lib already subclasses the editbox and has
thus already given it an id value.


----- Original Message -----
From: "Martin Stachon" <martin.stachon at worldonline.cz>
To: "EUforum" <EUforum at topica.com>
Sent: Saturday, July 13, 2002 10:22 PM
Subject: [win32lib] subclassing Combo's EditText


>
> I need to set some handlers for EditText field of ComboBox.
> I tried to subclass it according to this example from Microsoft:
>
> <c code>
>     /* Get the edit window handle for each combo box. */
>     pt.x = 1;
>     pt.y = 1;
>
>     hwndEdit1 = ChildWindowFromPoint(hwndCombo1, pt);
>     hwndEdit2 = ChildWindowFromPoint(hwndCombo2, pt);
>
>     /*
>     * Change the window procedure for both edit windows
>     * to the subclass procedure.
>     */
>
>     lpfnEditWndProc = (WNDPROC) SetWindowLong(hwndEdit1,
>         GWL_WNDPROC, (DWORD) SubClassProc);
>
>     SetWindowLong(hwndEdit2, GWL_WNDPROC,
>         (DWORD) SubClassProc);
> </c code>
>
> <eu code>
>  -- subclass the edit control
>  pt = acquire_mem( 0, SIZEOF_POINT )
>  store(pt, ptX, 1) -- also tried [5,5];[10,10] etc.
>  store(pt, ptY, 1)
>  pComboBoxEdit = w32Func(ChildWindowFromPoint, {getHandle(pComboBox), pt})
>  ? pComboBoxEdit
>  release_mem(pt)
>  pComboBoxEdit = subClassControl( {EditText, pWin}, pComboBoxEdit)
>  ? pComboBoxEdit
> </eu code>
>
> But the output is:
> 0
> 0
> - this means that ChildWindowFromPoint failed. What I am doing wrong
> or is there another way to get handle of the EditText?
>
> Regards,
>       Martin Stachon
>
> martin.stachon at tiscali.cz
> http://www.webpark.cz/stachon
>
>
>
>