帮忙看一小段代码 有关问题！

帮忙看一小段代码 问题！！！！
Identification()

  '传入参数
  Dim ClassName, cPage, cUrl, tTypeID, cType, wSql
  Dim sID, sTitle, sNum

  ClassName = SafeRequest("Action",0)

  tTypeID = SafeRequest("TypeID",1)
  If tTypeID <> "" Then
  cType = "?TypeID=" & cType
  wSql = "n.nType = "& tTypeID &" AND"
  End If

  cPage = SafeRequest("Page",1)
  If cPage = "" Then
  cUrl = "Diagramtext.Asp" & cType
  Else
  If cType <> "" Then
  cUrl = "Diagramtext.Asp"& cType &"&Page=" & cPage
  Else
  cUrl = "Diagramtext.Asp?Page=" & cPage
  End If
  End If

  Select case ClassName
  case "cTop"
  cInfocTop
  case "Del"
  cInfoDel
  case "GoPage"
  Response.Redirect("Diagramtext.Asp?Page=" & Request.Form("PageKey"))
  End Select
  %>

这段代码 哪里能看出TypeID后面为空

------解决方案--------------------
If tTypeID <> "" Then
cType = "?TypeID=" & cType
wSql = "n.nType = "& tTypeID &" AND"
End If