学习检测参数是否的为空的Function

因为所输入的参数类型不同，所以判断的方法也不一样。如何正确的判断参数是否为空？

具体的请看下文所示：

<%
'Check a variable isn't "empty"
Function IsBlank(ByRef TempVar)

'by default, assume it's not blank
IsBlank = False

'now check by variable type
Select Case VarType(TempVar)

'Empty & Null
Case 0, 1
IsBlank = True

'String
Case 8
If Len(TempVar) = 0 Then
IsBlank = True
End If

'Object
Case 9
tmpType = TypeName(TempVar)
If (tmpType = "Nothing") Or (tmpType = "Empty") Then
IsBlank = True
End If

'Array
Case 8192, 8204, 8209
'does it have at least one element?
If UBound(TempVar) = -1 Then
IsBlank = True
End If
End Select
End Function
%>

Example Usage
<%
If IsBlank(Session("username"))Then
response.redirect("LoginFail.htm")
End If
%>