For I = Len(strFileName) To 1 Step -1
'文件名中不允许有"\"字符，如先返回"\"则此文件没有后缀
If Mid$(strFileName, I, 1) = "\" Then
GetFileSuffix = ""
Exit Function
End If
If Mid$(strFileName, I, 1) = "." Then
GetFileSuffix = Mid$(strFileName, I)
Exit Function
End If
Next I
End Function
