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Purpose |
In a Callback Function, return the
CBCTLMSG has been superceded by the CB Callback functions, although CBCTLMSG remains supported for a limited period. Existing code should be converted to the new syntax as soon as possible. |
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Syntax |
CtlMsg& = CBCTLMSG |
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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). CBCTLMSG will return the numeric value of the notification message if CBMSG = %WM_COMMAND. For other values of CBMSG, CBCTLMSG will return message-dependent values. In other words, CBCTLMSG can only return a valid notification message value if CBMSG indicates that the message includes a notification message. That is, when CBMSG = %WM_COMMAND, CBCTLMSG will contain a notification message value sent by the originating control. For example, CBCTLMSG = %BN_CLICKED when the user clicks a button. 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 high-order word of the wParam& parameter. Therefore, CBCTLMSG is functionally equivalent to HI(WORD, wParam&) in a conventional Callback Function, and equivalent to HI(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 ButtonCallback() AS LONG SELECT CASE CBMSG CASE %WM_COMMAND IF CBCTL = %ID_OK AND CBCTLMSG = %BN_CLICKED THEN MSGBOX "Button was clicked!", %MB_TASKMODAL FUNCTION = 1 EXIT FUNCTION END IF END SELECT END FUNCTION |