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class session variables

I finally got class session variables to work by putting the following in
global.asax in the session_start:
dim myDBComp as DBComp = new DBComp........
session("myDBComp") = myDBComp

In each aspx codebehind module I can define my object right after the class
definition as so:
dim myDBComp as DBComp

The problem I had was where to put the instantiation:
myDBComp = CType(session("myDBComp"), DBComp)

I can't put it up with the definition as the compiler wants only
declarations up there.
I can't put it in any of the methods because it loses scope outside the
methods.
I finally found that it works if I put in in initializecomponent()

But then it disappears if I make any changed to the UI in the aspx page.

Where is it supposed to go?
Thanks,
Dean
Nov 17 '05 #1
4 1528
The instantiation will last the object while the page object exists. Putting
it in page_init or page_load, will mean this variable is set until the page
finishes executing.

"Dean" <de*********@earthlink.net> wrote in message
news:ea**************@TK2MSFTNGP10.phx.gbl...
I finally got class session variables to work by putting the following in
global.asax in the session_start:
dim myDBComp as DBComp = new DBComp........
session("myDBComp") = myDBComp

In each aspx codebehind module I can define my object right after the class definition as so:
dim myDBComp as DBComp

The problem I had was where to put the instantiation:
myDBComp = CType(session("myDBComp"), DBComp)

I can't put it up with the definition as the compiler wants only
declarations up there.
I can't put it in any of the methods because it loses scope outside the
methods.
I finally found that it works if I put in in initializecomponent()

But then it disappears if I make any changed to the UI in the aspx page.

Where is it supposed to go?
Thanks,
Dean

Nov 17 '05 #2
Marina:
According to a test that I just ran, it went out of scope as soon as the
page_load event ended. Page_init is part of the "web form designer
generated code", in fact initializecomponent() is called from there so
manually entered code gets clobbered there just like code in initialize
component.

So, unless I have made a mistake in my test, question still stands.
thanks,
Dean

"Marina" <mz*******@hotmail.com> wrote in message
news:ui**************@tk2msftngp13.phx.gbl...
The instantiation will last the object while the page object exists. Putting it in page_init or page_load, will mean this variable is set until the page finishes executing.

"Dean" <de*********@earthlink.net> wrote in message
news:ea**************@TK2MSFTNGP10.phx.gbl...
I finally got class session variables to work by putting the following in global.asax in the session_start:
dim myDBComp as DBComp = new DBComp........
session("myDBComp") = myDBComp

In each aspx codebehind module I can define my object right after the

class
definition as so:
dim myDBComp as DBComp

The problem I had was where to put the instantiation:
myDBComp = CType(session("myDBComp"), DBComp)

I can't put it up with the definition as the compiler wants only
declarations up there.
I can't put it in any of the methods because it loses scope outside the
methods.
I finally found that it works if I put in in initializecomponent()

But then it disappears if I make any changed to the UI in the aspx page.

Where is it supposed to go?
Thanks,
Dean


Nov 17 '05 #3
If the variable is declared at the class level, and initialized in page_init
or page_load, it will stick around for the lifetime of the page - which is
just until it finishes executing and when the response is sent to the
browser.

If you are declaring the variable inside a method - then it will have only
the scope of the method. This is why it has to be a class level variable.
After that, you can initialize it where ever you want - and it will stay
around for the lifetime of the object.

I don't know what test you did, but this is how it works. You can put code
into page_init - initializecomponent is meant for designer generated code.
page_init is yours to customize, those people usually use page_load.
"Dean" <de*********@earthlink.net> wrote in message
news:%2****************@TK2MSFTNGP11.phx.gbl...
Marina:
According to a test that I just ran, it went out of scope as soon as the
page_load event ended. Page_init is part of the "web form designer
generated code", in fact initializecomponent() is called from there so
manually entered code gets clobbered there just like code in initialize
component.

So, unless I have made a mistake in my test, question still stands.
thanks,
Dean

"Marina" <mz*******@hotmail.com> wrote in message
news:ui**************@tk2msftngp13.phx.gbl...
The instantiation will last the object while the page object exists.

Putting
it in page_init or page_load, will mean this variable is set until the

page
finishes executing.

"Dean" <de*********@earthlink.net> wrote in message
news:ea**************@TK2MSFTNGP10.phx.gbl...
I finally got class session variables to work by putting the following in global.asax in the session_start:
dim myDBComp as DBComp = new DBComp........
session("myDBComp") = myDBComp

In each aspx codebehind module I can define my object right after the

class
definition as so:
dim myDBComp as DBComp

The problem I had was where to put the instantiation:
myDBComp = CType(session("myDBComp"), DBComp)

I can't put it up with the definition as the compiler wants only
declarations up there.
I can't put it in any of the methods because it loses scope outside the methods.
I finally found that it works if I put in in initializecomponent()

But then it disappears if I make any changed to the UI in the aspx page.
Where is it supposed to go?
Thanks,
Dean



Nov 17 '05 #4
There is deffinitely a difference in the life of a component depending if it
is initialized in Page_init or Page load:
I first declare my component at the class level of my page as follows:
Dim myDBProc As PhotoDBProcs

I then initialize it in the page_load as follows:

myDBProc = CType(Session("myDBProc"), PhotoDBProcs)

I use the component to build content and, at the end of the page_load it
response is sent to the browser.

One of the buttons gets pushed triggering an event on the page. In the
button event the component no longer exists.

When I initialize this component in InitializeComponent() (or page_init),
however, the component still exists when the button is pushed.

Your first paragraph on your response is technicaly true but that is not
sufficient for any real application that has many interactions on a page.

So, to get the necessary scope of life on this component, I need to
initialize it in InitializeComponent() and re insert it each time it gets
wiped out upon UI change.

"Marina" <mz*******@hotmail.com> wrote in message
news:Ok**************@TK2MSFTNGP12.phx.gbl...
If the variable is declared at the class level, and initialized in page_init or page_load, it will stick around for the lifetime of the page - which is
just until it finishes executing and when the response is sent to the
browser.

If you are declaring the variable inside a method - then it will have only
the scope of the method. This is why it has to be a class level variable.
After that, you can initialize it where ever you want - and it will stay
around for the lifetime of the object.

I don't know what test you did, but this is how it works. You can put code into page_init - initializecomponent is meant for designer generated code.
page_init is yours to customize, those people usually use page_load.
"Dean" <de*********@earthlink.net> wrote in message
news:%2****************@TK2MSFTNGP11.phx.gbl...
Marina:
According to a test that I just ran, it went out of scope as soon as the
page_load event ended. Page_init is part of the "web form designer
generated code", in fact initializecomponent() is called from there so
manually entered code gets clobbered there just like code in initialize
component.

So, unless I have made a mistake in my test, question still stands.
thanks,
Dean

"Marina" <mz*******@hotmail.com> wrote in message
news:ui**************@tk2msftngp13.phx.gbl...
The instantiation will last the object while the page object exists.

Putting
it in page_init or page_load, will mean this variable is set until the

page
finishes executing.

"Dean" <de*********@earthlink.net> wrote in message
news:ea**************@TK2MSFTNGP10.phx.gbl...
> I finally got class session variables to work by putting the following
in
> global.asax in the session_start:
> dim myDBComp as DBComp = new DBComp........
> session("myDBComp") = myDBComp
>
> In each aspx codebehind module I can define my object right after
the class
> definition as so:
> dim myDBComp as DBComp
>
> The problem I had was where to put the instantiation:
> myDBComp = CType(session("myDBComp"), DBComp)
>
> I can't put it up with the definition as the compiler wants only
> declarations up there.
> I can't put it in any of the methods because it loses scope outside

the > methods.
> I finally found that it works if I put in in initializecomponent()
>
> But then it disappears if I make any changed to the UI in the aspx page. >
> Where is it supposed to go?
> Thanks,
> Dean
>
>



Nov 17 '05 #5

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