由于各种字段属性不同，判断字段是否为空的方法也各异．

下面是一个通用函数，免去了还要看字段类型之苦．

'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

应用实例： 
If IsBlank(rs("upic")) Then
  upicurl="/images/nonepic.jpg"
 Else
  upicurl=rs("upic")
 End If