view state and data binding

[Sergey Krutous]

Hi.
I am developing composite web control which contains a ListBox. I'd like
to minimize the amount of data transfered in view state to the client and
back, so I set to false EnableViewState property of the ListBox and
populated it by DataBind method. But in such scenario ListBox's
SelectedIndex property always returns -1 on postbacks.
Could you please answer is it possible to know what item was selected by
user in ListBox with view state disabled? What method or event should I
handle in the page's (or control's) life cycle?
I thought such properties as what item was selected in a ListBox are not
retrieved from view state. Browser can not change VIEWSTATE hidden variable,
it (VIEWSTATE variable) can even be protected from tampering by setting
EnableViewStateMac property to true. So browser should post back such
properties in some other way. Am I not right?

Best regards.
Sergey Krutous.

[Brock Allen]

In ASP.NET v1.x much of the behavior of controls (so things like SelectedIndexChange
events) relies upon ViewState. This is fixed in ASP.NET 2.0 with something
called ControlState which is in essence a section of ViewState that you can't
disable. The portion of ViewState you can diable only contains the data (not
the behavior) of the control.

So for now, you must enable ViewState.

-Brock
DevelopMentor
http://staff.develop.com/ballen

Hi.
I am developing composite web control which contains a ListBox.
I'd like
to minimize the amount of data transfered in view state to the client
and
back, so I set to false EnableViewState property of the ListBox and
populated it by DataBind method. But in such scenario ListBox's
SelectedIndex property always returns -1 on postbacks.
Could you please answer is it possible to know what item was
selected by
user in ListBox with view state disabled? What method or event should
I
handle in the page's (or control's) life cycle?
I thought such properties as what item was selected in a ListBox
are not
retrieved from view state. Browser can not change VIEWSTATE hidden
variable,
it (VIEWSTATE variable) can even be protected from tampering by
setting EnableViewStateMac property to true. So browser should post
back such properties in some other way. Am I not right?

Best regards.
Sergey Krutous.