dim flag as boolean '全局

Public Function MyKBHook(ByVal ncode As Long, ByVal wParam As Long, ByVal lParam As Long) As Long
    On Error Resume Next
    if flag then 
       Call CallNextHookEx(hHook, ncode, wParam, lParam)
       flag=false
       exit function
    endif
    MyKBHook = 0
    If ncode = 0 Then
        If wParam = WM_KEYDOWN Then
            CopyMemory mymsg, ByVal lParam, Len(mymsg)
            If mymsg.vKey = 65 Then
                flag=true
                Call keybd_event(66, 0, KEYEVENTF_KEYDOWN, 0)
                MyKBHook = 1
            ElseIf mymsg.vKey = 66 Then
                flag=true
                Call keybd_event(65, 0, KEYEVENTF_KEYDOWN, 0)
                MyKBHook = 1
            End If
        End If
    End If
    Call CallNextHookEx(hHook, ncode, wParam, lParam)
End Function