WM_GETTEXTLENGTH

2.x

WM_GETTEXTLENGTH
wParam = 0;     /* not used, must be zero */
lParam = 0L;    /* not used, must be zero */

An application sends a WM_GETTEXTLENGTH message to determine the length, in bytes, of the text associated with a window. The length does not include the terminating null character.

Parameters

This message has no parameters.

Return Value

The return value is a word specifying the length, in bytes, of the text.

Comments

For an edit control, the text to be copied is the contents of the edit control. For a combo box, the text is the contents of the edit-control (or static-text) portion of the combo box. For a button, the text is the button name. For other windows, the text is the window title. To determine the length of an item in a list box, an application can use the LB_GETTEXTLEN message.

Example

This example enables the push button in a dialog box if the user has entered text in an edit control in the dialog box:

case ID_MYEDITCONTROL:
    if (HIWORD(lParam) == EN_CHANGE)
        EnableWindow(GetDlgItem(hdlg, IDOK),
            (BOOL) SendMessage(LOWORD(lParam),
            WM_GETTEXTLENGTH, 0, 0L));
    return TRUE;