Re: Session Madness

Well Kevin, whatever the truth behind the problem, your suggestion saved the
day. I implemented it from within the Menu object. I'm not sure if I really
needed to prefix the menuList identifier with the ControlID, but I was
erring on the side of duplicate ID's. But in this instance, the ID's are
allways likley to be the same anyway so I dont think it matters.

Public Sub SaveInSession()
If Me.Page.Session(Me.ID & "_" & "menuList") Is Nothing Then
Me.Page.Session(Me.ID & "_" & "menuList") = menuList
End If
End Sub

Public Sub RetreiveFromSession()
menuList = Me.Page.Session(Me.ID & "_" & "menuList")
m_count = menuList.Count
End Sub

And in the Page. . . .

'Check is this is already in Session
If Not Page.IsPostBack Then

'Build the menu
Menu1.Add(New TONEControls.Menu.MenuItem("MItem",
"default.aspx", "Home", False, True))
Menu1.Add(New TONEControls.Menu.MenuItem("MItem",
"CreateExpenses.aspx", "New Expenses", False, False))
Menu1.Add(New TONEControls.Menu.MenuItem("MItem", "Review.aspx",
"Review", False, False))
'Add it
Menu1.SaveInSession()

Else

'Get it from session
Menu1.RetreiveFromSession()

End If

Menu1.SetSelected(0)

As allways thanks for taking the time to reply. The issue regarding process
vs data makes sense even if we have not uncovered the underlying problem.

--
Best Regards

The Inimitable Mr Newbie º¿º



"Kevin Spencer" <kevin@xxxxxxxxxxxxxxxxxxxxxxxxxx> wrote in message
news:%238gyr565FHA.1248@xxxxxxxxxxxxxxxxxxxxxxx
> Howdy Mr N.,
>
> I kind of suspected that the Control was registered in the Page, and
> defined in the CodeBehind. I cannot be sure of this, but I believe this
> has something to do with why the Control is not being rendered as
> expected, which also brings me to my second point, about which you asked.
> That is, that it is not a good idea to store UI elements in Session. So,
> I'll start with that.
>
> First, Session exists for every user that is currently using the
> application. Whatever users are visiting this particular page, they will
> have a copy of the Contro in their Session State. This means that storing
> the Control in Session creates a larger footprint (multiplied by the
> number of Sessions in which it is stored) than storing only the data. The
> Control is a UI element, and therefore contains data and process which
> does not need to be stored in memory. Controls are instantiated with each
> Request, and pass out of scope when the Page class exits ( matter of
> milliseconds), ensuring that they will be Garbage Collected, freeing up
> server memory resources. Anything stored in Session remains in state until
> the Session is destroyed, which by definition means at least 20 minutes
> (after the user has stopped sending Requests for 20 minutes). In other
> words, a good rule of thumb is to keep anything that doesn't need to be in
> Session out of Session.
>
> In addition, this Control is instantiated by the Page class when a Request
> is received. Now you have 2 instances of the Control, one more than
> necessary, and one which will be discarded in short order, making it
> irrelevant. Let's say that you *did* have a reson for storing a Control in
> Session (I can't think of one, but for the sake of argument...). There is
> therefore no need to have one registred in the page. The Control can be
> dynamically added to the Page at run-time.
>
> And that brings me back to the root of your problem. I believe there is a
> conflict occurring between the Control registred in the Page, and the
> Control stored in Session. It has something to do with (forgive me for not
> taking the time to investigate fully) the order in which Controls are
> created, stored, and rendered in a Templated Control that contains Child
> Controls (the Page). I believe that the Session Control is probably not
> being loaded at the right time in the sequence (most probably - remember
> our discussion about CreateChildControls?). Somehow, the registred Control
> is the one being rendered.
>
> What I would do (and in fact, have done in an app with a very similar type
> of menu) is to keep the registered Control in the page, store the
> ArrayList in Session, and load the Control from the ArrayList at run-time.
>
> Again, forgive me for not having the time to look extensively into the
> exact details. I do love to research, but my wife wants me to spend some
> time with her!
>
> --
> HTH,
>
> Kevin Spencer
> Microsoft MVP
> .Net Developer
> There's a seeker born every minute.
> - Dr. "Happy" Harry Cox
>
> "Mr Newbie" <here@xxxxxxx> wrote in message
> news:ewfVWm55FHA.2628@xxxxxxxxxxxxxxxxxxxxxxx
>> Thanks for your reply Kevin,
>>
>> OK to answer your questions.
>>
>> 1. How is it created.
>> The Custom Control, is just that, it resides in a library which is part
>> of the web solution. The menu is a simple table creation which uses css
>> to set the background mouseover, mouseout and click events.
>>
>> The control has an ArrayList collection inside it which stores objects
>> instantiated from a nested class within the control. These objects are
>> the menu items themselves containing properties such as href, IsSelected,
>> class ( style *** class ) etc.
>>
>> The overriden Render sub takes responsibility for setting up the
>> javascript for style switching when the mouse events go off.
>>
>> 2.Where
>> The control is registered as normal as a custom control in the page
>> template an its ID is Menu1, and is defined in the Codebehind for the
>> Page.
>>
>> During Page_Load, we detect if the control has been stored in session and
>> if not, we create the Menu using its Add method and instantiating the
>> MenuItem anonymously in the constructor. If the Menu has already been
>> stored we assign its Session("Menu") reference to Menu1. So far so good,
>> we then select the MenuItem which is currently selected depending on the
>> page it's on. And this is highlighted as the current position on the site
>> ( Current Page ).
>>
>> Everything is fine UNTIL we enter the Render event of the Menu control on
>> Postback, and although we are in an object, its menuList ( ArrayList
>> containing the items ) is empty and the count is also empty as if it has
>> been freshly instantiated.
>>
>> I'm obviously missing something basic, I hope you will be able to shed
>> some light on it.
>>
>> PS: Why is it bad to store the UI objects in Session ( Just interested to
>> know )
>>
>> Best Regards
>>
>> The Inimitable Mr Newbie º¿º
>>
>>
>>
>>
>> "Kevin Spencer" <kevin@xxxxxxxxxxxxxxxxxxxxxxxxxx> wrote in message
>> news:%23Mi5yL55FHA.636@xxxxxxxxxxxxxxxxxxxxxxx
>>> How and where is the Menu Control created?
>>>
>>> Just as a note, it is generally bad practice to store UI elements in
>>> Session. It is better to store the data they contain in Session.
>>>
>>> --
>>> HTH,
>>>
>>> Kevin Spencer
>>> Microsoft MVP
>>> .Net Developer
>>> Complex things are made up of
>>> Lots of simple things.
>>>
>>> "Mr Newbie" <here@xxxxxxx> wrote in message
>>> news:upQ9cZ35FHA.3136@xxxxxxxxxxxxxxxxxxxxxxx
>>>>I have written a Custom Control Menu. Its fairly simple but it works
>>>>well enough. In order to simplify things I decided to store the Menu1
>>>>custom control in Session. In the page load event below, it retreives
>>>>the Menu from session and assigns its reference to Menu1.
>>>>
>>>> Within the Page_Load event I can see its internal values which have
>>>> been retreived for each menu item and so it looks good. However, when
>>>> the Render method is called of Menu1, everything seems to have
>>>> disapeared, there are no menuitems and the count is zero.
>>>>
>>>> Im sure I am doing something fundamentally stupid, but I cant see it
>>>> for staring !
>>>>
>>>> Does anyone have a clue ?
>>>>
>>>> 'Check is this is already in Session
>>>>
>>>> If (Session("Menu") Is Nothing) Then
>>>>
>>>> 'Build the menu
>>>>
>>>> Menu1.Add(New TONEControls.Menu.MenuItem("MItem", "default.aspx",
>>>> "Home", False, True))
>>>>
>>>> Menu1.Add(New TONEControls.Menu.MenuItem("MItem",
>>>> "CreateExpenses.aspx", "New Expenses", False, False))
>>>>
>>>> Menu1.Add(New TONEControls.Menu.MenuItem("MItem", "Review.aspx",
>>>> "Review", False, False))
>>>>
>>>> 'Add it
>>>>
>>>> Session("Menu") = Menu1
>>>>
>>>> Else
>>>>
>>>> 'Get it from session
>>>>
>>>> Menu1 = Session("Menu")
>>>>
>>>> End If
>>>>
>>>> Menu1.SetSelected(0)
>>>>
>>>>
>>>> --
>>>> Best Regards
>>>>
>>>> The Inimitable Mr Newbie º¿º
>>>>
>>>
>>>
>>
>>
>
>


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