Subclassing DDT

[Guest]

I know there was an example or article posted sometime ago about subclassing and I would like to learn how to do it. I looked for it earlier but wasn't able to find it. Maybe I didn't go far enough back. I want to just simply learn how to subclass ddt controls in general. If someone knows the url for that,would you be so kind as to let me know what that is?

Thanks,
Adam

[Guest]

Never mind y'all, I found Lance's example on subclassing an edit control in a ddt window.

Regards,
Adam

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[Bruce Singleton]

Adam
Where did you locate Lance's example? I cannot find it.

Bruce



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[Guest]

hi bruce,
i had to dig way back for this:

it's a pretty straight forward example and i had no problem adapting it to fit my needs. have fun.

regards,
adam

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[this message has been edited by adam ritchie (edited february 23, 2000).]

[Semen Matusovski]

as i remember, lance' sample is for subclassing alone edit control.
if you want to subclass whole ddt' window, look http://www.powerbasic.com/support/pb...ad.php?t=12662
up to now, lance didn't post information that it's not correct to replace dialog doevents by described way.


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[Guest]

Semen,
It is still a good example of subclassing in general and that is what I wanted. I had already investigated that link before I checked out Lance's example. I have been able to adapt it to work with any control I need it for. It depends on what Bruce wants to do - subcalss the whole window or just a control(s). I haven't tried it on the whole window yet(at this point I don't need to).

Regards,
Adam

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[Bruce Singleton]

Thanks Adam & Seman

This should do it. Thanks again

Bruce


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[Scott Turchin]

Here's my sample of how to subclass an edit control so that only the letters A-F and 0-9 may appear. (representing Hex values of course!)

'Create a DDT edit box, labeled %IDTEXT1
'In main dialog procedure:
    Case %WM_INITDIALOG
         ' Subclass the edit control
         Control Handle CbHndl, %IDTEXT1 To hEdit&
         gOldSubClassProc = SetWindowLong(hEdit&, %GWL_WNDPROC, CodePtr(SubClassProc))  


    Case %WM_DESTROY
      ' Important! Remove the subclassing
      SetWindowLong hEdit&, %GWL_WNDPROC, gOldSubClassProc
      Function = 0
      Exit Function

'Now the subclass procedure:
'Not 100% sure this is all accurate, but it does work...:-)

'------------------------------------------------------------
Function SubClassProc(ByVal hWnd&, ByVal wMsg&, ByVal wParam&, ByVal lParam&) As Long
    Local NewChar As Asciiz * 2
    Local Y       As Long
    Local zText   As Asciiz * 13
    Local yMsg    As Long
' Process our messages in this subclass procedure
Select Case wMsg&
    Case %WM_KEYDOWN
         yMsg = LoWrd(wParam&) 'Actual ascii value of keystroke coming in
         Select Case yMsg
         Case 8,48 To 57, 65 To 70, 97 To 102
            ' do nothing
         Case 35,36,37,39,40,46
            ' do nothing
'     Left arrow = 37
'     Right arrow = 39
'     home = 36
'     Down = 40
'     Up = 38
'     End = 35
         Case Else
            Function = %NULL
            Exit Function
         End Select
    Case %WM_CHAR
         yMsg = LoWrd(wParam&) 'Actual ascii value of keystroke coming in
         Select Case yMsg
         Case 8 'BackSpace
         Case 48 To 57 ,65 To 70
         Case 97 To 102 'a-f
         Case Else
             Function = %NULL
             Exit Function
         End Select

    Case %WM_KEYUP
         Control Get Text hDlg, %IDTEXT1 To St
         If Len(St) = 12  Then
            Control Enable hDlg, %IDSWAP
         Else
            Control Disable hDlg, %IDSWAP
         End If
End Select
' Pass the message on to the original window procedure... the DDT engine!
Function = CallWindowProc(gOldSubClassProc, hWnd&, wMsg&, wParam&, lParam&)
End Function
'-------------------------------------------------------------------------------

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Scott Turchin