请教:《windows程序设计》中的问题?
p363
LRESULT CALLBACK ScrollProc (HWND hwnd, UINT message,
WPARAM wParam, LPARAM lParam)
{
int id = GetWindowLong (hwnd, GWL_ID) ;
switch (message)
{
case WM_KEYDOWN :
if (wParam == VK_TAB)
SetFocus (GetDlgItem (GetParent (hwnd),
(id + (GetKeyState (VK_SHIFT) < 0 ? 2 : 1)) % 3)) ;
break ;
case WM_SETFOCUS :
idFocus = id ;
break ;
}
//下面这句话书上说使用CallWindowProc调用旧的滚动条窗口过程,旧的在哪里??
//具体的代码在书上,
return CallWindowProc (OldScroll[id], hwnd, message, wParam,lParam);
}