The WM_NEXTDLGCTL message is sent to a dialog box procedure to set the keyboard focus to a different control in the dialog box. WM_NEXTDLGCTL wCtlFocus = wParam; // identifies control for focus fHandle = (BOOL) LOWORD(lParam); // wParam handle flag ParameterswCtlFocusValue of wParam. If the fHandle parameter is TRUE, the wCtlFocus parameter identifies the control that receives the focus. If fHandle is FALSE, wCtlFocus is a flag that indicates whether the next or previous control with the WS_TABSTOP style receives the focus. If wCtlFocus is zero, the next control receives the focus; otherwise, the previous control with the WS_TABSTOP style receives the focus. fHandleValue of lParam. Contains a flag that indicates how Windows uses the wCtlFocus parameter. If the fHandle parameter is TRUE, wCtlFocus is a handle associated with the control that receives the focus; otherwise, wCtlFocus is a flag that indicates whether the next or previous control with the WS_TABSTOP style receives the focus.
The WM_NEXTDLGCTL message is sent to a dialog box procedure to set the keyboard focus to a different control in the dialog box. WM_NEXTDLGCTL wCtlFocus = wParam; // identifies control for focus fHandle = (BOOL) LOWORD(lParam); // wParam handle flag ParameterswCtlFocusValue of wParam. If the fHandle parameter is TRUE, the wCtlFocus parameter identifies the control that receives the focus. If fHandle is FALSE, wCtlFocus is a flag that indicates whether the next or previous control with the WS_TABSTOP style receives the focus. If wCtlFocus is zero, the next control receives the focus; otherwise, the previous control with the WS_TABSTOP style receives the focus. fHandleValue of lParam. Contains a flag that indicates how Windows uses the wCtlFocus parameter. If the fHandle parameter is TRUE, wCtlFocus is a handle associated with the control that receives the focus; otherwise, wCtlFocus is a flag that indicates whether the next or previous control with the WS_TABSTOP style receives the focus.
wCtlFocus = wParam; // identifies control for focus
fHandle = (BOOL) LOWORD(lParam); // wParam handle flag
ParameterswCtlFocusValue of wParam. If the fHandle parameter is TRUE, the wCtlFocus parameter identifies the control that receives the focus. If
fHandle is FALSE, wCtlFocus is a flag that indicates whether the next or previous control with the WS_TABSTOP style receives the focus. If wCtlFocus is zero, the next control receives the focus; otherwise, the previous control with the WS_TABSTOP style receives the focus. fHandleValue of lParam. Contains a flag that indicates how Windows uses the wCtlFocus parameter. If the fHandle parameter is TRUE, wCtlFocus is a handle associated with the control that receives the focus; otherwise, wCtlFocus is a flag that indicates whether the next or previous control with the WS_TABSTOP style receives the focus.
wCtlFocus = wParam; // identifies control for focus
fHandle = (BOOL) LOWORD(lParam); // wParam handle flag
ParameterswCtlFocusValue of wParam. If the fHandle parameter is TRUE, the wCtlFocus parameter identifies the control that receives the focus. If
fHandle is FALSE, wCtlFocus is a flag that indicates whether the next or previous control with the WS_TABSTOP style receives the focus. If wCtlFocus is zero, the next control receives the focus; otherwise, the previous control with the WS_TABSTOP style receives the focus. fHandleValue of lParam. Contains a flag that indicates how Windows uses the wCtlFocus parameter. If the fHandle parameter is TRUE, wCtlFocus is a handle associated with the control that receives the focus; otherwise, wCtlFocus is a flag that indicates whether the next or previous control with the WS_TABSTOP style receives the focus.
" Messages单元： Line:102"
如何看到Messages单元的内容，不见有Messages.pas这个文件啊？
或者
...\delphi7\source\rtl\win\messages.pas