Detect keypress in a DDT textbox

[Wayne Diamond]

This is probably blindingly simple, but I couldnt find any references in my beloved POFFS...
Basically I need to be able to detect when Enter is pressed in a DDT textbox
Thanks!
Hope youre all enjoying the start of the weekend


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[Borje Hagsten]

Not entirely simple, but following is one way of doing it:

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' Test of subclassed textbox and Enter-key trap
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#COMPILE EXE
#INCLUDE "WIN32API.INC"
 
%ID_TEXT = 10                         'Id for textbox
GLOBAL hEdit AS LONG, oldTxtproc AS LONG  'for address of original textbox procedure
DECLARE CALLBACK FUNCTION DlgProc
DECLARE CALLBACK FUNCTION TextWndProc
 
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' Create dialog and controls, etc
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FUNCTION PBMAIN
  LOCAL hDlg AS LONG
 
  DIALOG NEW 0, "Textbox test..", , , 120, 46, %WS_CAPTION or%WS_SYSMENU, 0 TO hDlg
 
  CONTROL ADD TEXTBOX, hDlg, %ID_TEXT, "", 2, 2, 116, 12, _
                       %WS_CHILD OR %WS_HSCROLL, %WS_EX_CLIENTEDGE
  CONTROL HANDLE hDlg, %ID_TEXT TO hEdit
 
  oldTxtproc = SetWindowLong(hEdit, %GWL_WNDPROC, CODEPTR(TextWndProc)) 'Subclass Edit control
 
  DIALOG SHOW MODAL hDlg CALL DlgProc
 
END FUNCTION
 
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' Main dialog's message handler
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CALLBACK FUNCTION DlgProc
  SELECT CASE CBMSG
     CASE %WM_DESTROY
        IF oldTxtproc THEN SetWindowLong hEdit, %GWL_WNDPROC, oldTxtproc      'Restore from subclass at exit
 
  END SELECT
END FUNCTION
 
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' Textbox's subclassed message handler
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CALLBACK FUNCTION TextWndProc
  SELECT CASE CBMSG
     CASE %WM_KEYUP
        IF CBWPARAM = %VK_RETURN THEN MSGBOX "Enter was pressed"
 
  END SELECT
  FUNCTION = CallWindowProc(oldTxtproc, CBHNDL, CBMSG, CBWPARAM, CBLPARAM)
END FUNCTION

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Corrected un-subclassing to WM_DESTROY after tips from Lance.

[This message has been edited by Borje Hagsten (edited April 20, 2001).]

[Wayne Diamond]

Thanks Borje - thats a bit trickier than I thought it would've been, but it works as required nonetheless, thanks!


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[Lance Edmonds]

Unfortunately, Borje is unsubclasing the control long after it has been destroyed... this is an incorrect technique.

The unsubclass code should be placed in the %WM_DESTROY handler of the dialog callback. Search the Source Code Forum subject titles for "subclass" and you'll find my original code for this that shows how to clean up correctly.


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Lance
PowerBASIC Support
mailto:[email protected][email protected]</A>

[Borje Hagsten]

Ah - sorry, I have corrected the code above..

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