'以独占方式打开 如果捕获到错误就是被占用了
代码如下：
Private Function FileIsOpen(ByVal FilePath As String) As Boolean
Dim fFile As Integer
fFile = FreeFile
On Error GoTo ErrOpen
Open FilePath For Binary Lock Read Write As fFile
Close fFile
Exit Function
ErrOpen:
FileIsOpen = True
End Function