关于释放session的两篇文章（二） -pc6资讯

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关于释放session的两篇文章（二） 时间：2004/11/7 4:10:00来源：本站整理作者：蓝点我要评论(0): Deleting a Subset of Session Variables

When using Sessions to store variables in, I use a naming convention - for example, for all Customer related info I prefix the session variable with the substring Customer. (so for the CustomerID it would be Customer.ID, the customer username would be Customer.Name, etc.) This is very useful when viewing the session objects as you can see the related objects straight off.

The problem I had the other day was that I wanted to remove only those items from the Session which were prefixed SW.. So first off I used the following code:

'---------------------------------------

Session("SW.1")="Test 1"

Session("SW.2")="Test 2"

Session("Other")="Other"

For Each SessionItem in Session.Contents

  If Left(SessionItem,3) = "SW." then

    Session.Contents.Remove(SessionItem)

  end if

Next

'---------------------------------------

This seems fine, but when it's run, what happens is that SW.1 is removed, but SW.2 is NOT removed. Why? I'm not exactly sure, but I guess that the index is then reset so that SW.2 is now where SW.1 was, and seeing as we have iterated past that item in the For Each...Next statement, the loop just moves to Other, missing out SW.2 altogether! Eek!

So to get round this I wrote the following function, which will properly delete all Session variables that begin with a specified substring:

'---------------------------------------

function SessionRemoveSelected(sItemPrefix)

'/////////////////////////////////////////////////

' Remove Selected Items starting with sItemPrefix

' from the Session. e.g. SS. will remove SS.ID and

' SS.NAME but not CustomerID Returns True or False

' depending on whether any items where removed.

'---------------------------------------

' sItemPrefix [string] : Item Prefix

'/////////////////////////////////////////////////

  dim arySession()

  dim lCount, lPrefixLength

  dim SessionItem

  dim blnResult



  lCount = -1

  lPrefixLength = len(sItemPrefix)

  blnResult = false



  ' temporarily store in array items to remove

  For Each SessionItem in Session.Contents

    if left(SessionItem,lPrefixLength) = sItemPrefix then

      lCount = lCount + 1

      redim preserve arySession(lCount)

      arySession(lCount) = SessionItem

    end if

  Next

  ' remove items

  if IsArray(arySession)and lCount >= 0 then

    for lCount = LBound(arySession) to UBound(arySession)

      Session.Contents.Remove(arySession(lCount))

    next

    blnResult=true

  end if

  SessionRemoveSelected = blnResult

end function

'-------------------------------------------------

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