That is, if multiple users are requesting or posting to the same page,
is the the code under app_code reentrant??? Why?

Thanks~!

"lander" <(E-Mail Removed)> wrote in message
news:cbc61d9b-32b4-4a81-a7ab-(E-Mail Removed)...
> That is, if multiple users are requesting or posting to the same page,
> is the the code under app_code reentrant??? Why?
>

I'm not sure you are using the term re-entrant appropriately I suspect you
mean is it threadsafe. The answer is: its up to you.

Normally classes that you may place in app_code that are then instanced by
ASPX pages will be threadsafe in that they are only being used by one thread
for the duration of the current request processing. However if you then
place instances such classes somewhere that can be accessed by more than one
thread (cache, static member etc) the responsibility for creating thread
safety is yours.


--
Anthony Jones - MVP ASP/ASP.NET

On 3ÔÂ8ÈÕ, ÏÂÎç8ʱ44·Ö, "Anthony Jones" <A...@yadayadayada.com> wrote:
> "lander" <lostlander....@gmail.com> wrote in message
>
> news:cbc61d9b-32b4-4a81-a7ab-(E-Mail Removed)...
>
> > That is, if multiple users are requesting or posting to the same page,
> > is the the code under app_code reentrant??? Why?
>
> I'm not sure you are using the term re-entrant appropriately I suspect you
> mean is it threadsafe. The answer is: its up to you.
>
> Normally classes that you may place in app_code that are then instanced by
> ASPX pages will be threadsafe in that they are only being used by one thread
> for the duration of the current request processing. However if you then
> place instances such classes somewhere that can be accessed by more than one
> thread (cache, static member etc) the responsibility for creating thread
> safety is yours.
>
> --
> Anthony Jones - MVP ASP/ASP.NET

Ok, i create one variable inside the page class, which is static and
its value is set in page_load, is it safe to do so?

"lander" <(E-Mail Removed)> wrote in message
news:78e2b82f-6517-4482-bc5f-(E-Mail Removed)...
>Ok, i create one variable inside the page class, which is static and
>its value is set in page_load, is it safe to do so?

No.

Static variables will be available across the whole app domain. It is
conceivable that two clients hitting the same page at the same time would
have two threads trying to modify that variable at the same time.

You will need to add some synchronising code such as:-

static SomeType ourValue = null;
static readonly object ourLock = new object();

public static void ValueMutator()
{
lock(ourLock);
{
// code that modified ourValue;
}
}

Of course the exact nature of the locking needed (if any) will depend on the
page logic.

--
Anthony Jones - MVP ASP/ASP.NET

On 3ÔÂ9ÈÕ, ÏÂÎç10ʱ31·Ö, "Anthony Jones" <A...@yadayadayada.com> wrote:
> "lander" <lostlander....@gmail.com> wrote in message
>
> news:78e2b82f-6517-4482-bc5f-(E-Mail Removed)...
>
> >Ok, i create one variable inside the page class, which is static and
> >its value is set in page_load, is it safe to do so?
>
> No.
>
> Static variables will be available across the whole app domain. It is
> conceivable that two clients hitting the same page at the same time would
> have two threads trying to modify that variable at the same time.
>
> You will need to add some synchronising code such as:-
>
> static SomeType ourValue = null;
> static readonly object ourLock = new object();
>
> public static void ValueMutator()
> {
> lock(ourLock);
> {
> // code that modified ourValue;
> }
>
> }
>
> Of course the exact nature of the locking needed (if any) will depend on the
> page logic.
>
> --
> Anthony Jones - MVP ASP/ASP.NET

Thanks very much!