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Purpose |
In a Callback Function, return the numeric
ID
value of the
CBCTL has been superceded by the CB Callback functions, although CBCTL remains supported for a limited period. Existing code should be converted to the new syntax as soon as possible. |
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Syntax |
Id& = CBCTL |
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Remarks |
When a user clicks on a button, types into a text box, or generally interacts with any control in a dialog, Windows sends a message to the callback for the control (or the dialog if the control does not have a callback). CBCTL returns the ID number as assigned to the control with the CONTROL ADD statement. CBCTL will return the ID of a control if CBMSG = %WM_COMMAND. For other values of CBMSG, CBCTL will return message-dependent values. If we consider a conventional callback procedure: FUNCTION DlgCallback(BYVAL hDlg???, BYVAL wMsg&, BYVAL wParam&, BYVAL lParam&) _ EXPORT AS LONG The notification message is sent to the callback as the low-order word of the wParam& parameter. Therefore, CBCTL is functionally equivalent to LO(WORD, wParam&) in a conventional Callback Function, and equivalent to LO(WORD, CBWPARAM) in a DDT Callback Function. |
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Restrictions |
This function is only valid inside a Callback Function. |
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See also |
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Example |
CALLBACK FUNCTION ComboCallback() AS LONG SELECT CASE CBMSG CASE %WM_COMMAND IF CBCTL = %IDCOMBO AND CBCTLMSG = %CBN_DBLCLK THEN CALL UpdateMyStatus() FUNCTION = 1 EXIT FUNCTION END IF CASE ... ... END FUNCTION |