最后,通过声明和调用Windows API函数(Windows应用程序接口函数),VB可以将触角伸向操作系统内部,以实现一些底层的功能。VB通过如下格式声明API函数: Private Declare Function SendMessage Lib "user32" Alias "SendMessageA" (ByVal hwnd As Long, ByVal wMsg As Long, ByVal wParam As Long, lParam As Any) As Long API函数一经声明即可像内部函数一样调用,不过调用时需注意函数返回值及参数类型。