ViewState v Session - Confused

[mosscliffe]

I am testing for how/when a page is posted back and I decided to use a
ViewState variable in PageLoad to set up a counter, but it appears,
the ViewState is cleared on each PageLoad. So then I used SESSION and
that worked.

Am I correct in assuming ViewState is cleared on each PageLoad or is my
code incorrect.

VIEWSTATE
If IsNothing(ViewState("PbCounter")) Then

ViewState("PBCounter") = 1
Else
ViewState("PBCounter") = Session("PBCounter") + 1
End If

SESSION
If IsNothing(Session("PbCounter")) Then

Session("PBCounter") = 1
Else
Session("PBCounter") = Session("PBCounter") + 1
End If

Response.write(ViewState("PBCounter").tostring) ALWAYS ONE

Response.write(Session("PBCounter").tostring) INCREMENTS CORRECTLY

Thanks - Richard

 

[Remy]

If this is really your code, then you are putting an empty Session
variable into the Viewstate.

VIEWSTATE
If IsNothing(ViewState("PbCounter")) Then
ViewState("PBCounter") = 1
Else
ViewState("PBCounter") = Session("PBCounter") + 1 <<<<<<<
HERE
End If

 

[mosscliffe]

Sorry Typo - with cut and paste, no it was correct in the actual code.
I did viewstate first and when it did not work I then changed it to
session.

 

[Kevin Spencer]

ViewState is stored in a Page, and passed back and forth to the client via a
hidden form field. Session is stored in Server memory. Therefore, ViewState
is scoped to a Page, but only to the Page after PostBack, not when it is
initially loaded. Session State is scoped to a single user Session, and
transcends Pages.

--
HTH,

Kevin Spencer
Microsoft MVP
Professional Numbskull

Hard work is a medication for which
there is no placebo.

 

[Greg Collins [InfoPath MVP]]

Thanks. That was helpful information.

 

[Edwin Knoppert]

Eh?

On first page request you should be able to add custom values.
On postback you should be able to obtain it again.
Am i missing something here, i believe i thave tested this a while ago.
Of course a viewstate is bounded to a page but that could be welcome.
+ when using a master page you could tag stuff to multiple 'pages' (imo)

 

[Kevin Spencer]

Yes, you can add values to it initially, but it is not stored. It is stored
in a hidden form field, which, when the page Posts Back, re-creates the
ViewState object from the field contents. In other words, if you add
something to a Page's ViewState, and navigate back to the same Page by any
means other then a PostBack, the ViewState will be empty.

--
HTH,

Kevin Spencer
Microsoft MVP
Professional Numbskull

Hard work is a medication for which
there is no placebo.