VB写快捷键出的问题

Private Declare Function GetAsyncKeyState Lib "user32" (ByVal vkey As Long) As Integer
Private Function MyHotKey(vKeyCode) As Boolean
'快捷键
MyHotKey = (GetAsyncKeyState(vKeyCode) < 0)
End Function
Private Sub Form_Load()
If MyHotKey(vbKeyF1) Then
   MsgBox "按下F1键", , "提示"
   End If
End Sub
为何我按下F1但没有提示呢？
哪里写错了么？？

这代码不能写load里的，要写timer里才有效果