Select.Case语句中，如果遇到null值的数据，应该怎样做判断？多谢

Select..Case语句中，如果遇到null值的数据，应该怎样做判断？谢谢
我试过
Case   Null是不行的，请问遇到NULL值的数据如何作判断？谢谢
Case   Else也不行的

------解决方案--------------------
kw=WorkStatus& " "

Select Case kw
Case "3 " DataStatusTracer = "a "
Case "4 " DataStatusTracer = "b "
Case "5 " DataStatusTracer = "c "
Case "6 " DataStatusTracer = "d "
Case " " DataStatusTracer = "f "
End Select

试试