Hi there,
I was previously able to store my AsyncResult to the Session with the
sessionstate mode="InProc" but now I get:

System.Web.HttpException: Unable to serialize the session state. Please
note that non-serializable objects or MarshalByRef objects are not
permitted when session state mode is 'StateServer' or 'SQLServer'.

Is there any way to serialize the AsyncResult or is there some other
workaround? It seems ridiculous that simply changing the mode of
session storage should have such a radical effect on the design of an
application.
Thanks,
Sean.

Hi,

Storing session in a memory cache within the same process and remotely in
the memory of another process is very different. InProc does not require
serialization therefore any references can be stored while session state
stored out of process has to be serialized for transmission.

With the teams I work with I usually recommend that they develop with using
the ASP.NET state service on the local machine. That way they do not get any
surprises when they need to deploy to a web farm environment.

--
Chris Taylor
http://dotnetjunkies.com/weblog/chris.taylor
<sean.swords (AT) gmail (DOT) com> wrote

Cheers Chris, and so can the AsyncResult object be serialized? How
should I go about this?
Thanks,
Sean

Chris Taylor wrote:

Hi!

No. You have to find another solution. You can keep the AsyncResults in a
static collection witch is always a in-memory structure:

class AsyncResultManager {

static Dictionary<string, IAsyncResult> _dic = new ...;

public IAsyncResult Get(string key){
return _dic[key];
}

public void Set(string key, IAsyncResult ar){
_dic[key] = ar;
}

}

Be be arware that every server within a web-farm maintains its own List.
Completing asyncron calls from another server that have begun it is not
supported (by every implementation I' aware of) anyway.


GP

Thanks for the tips guys but I opted for a considerably simpler option
that seems to work perfectly. I wanted to store the result in the
session so I could maintain separate asynchronous operations for each
logged in user. The cache can achieve the same functionality like so
(VB):
Cache("result" + Session.SessionID) = ar
Cheers

Günter Prossliner wrote:

Hi!

Ok. But be aware that:

* A new Session may get the same SessionID again (because when a Session
ends the cookie remains within the Browsers memory). So it is no bad idea to
clear the value from the cache within Session_Start

* Cache items may get removed from the Cache automaticly. There are memory -
limits for the cache. At least you should insert the objects with the
CacheItemPriority.NotRemovable.

I would still recommend that you use static Fields instead of the Cache to
avoid the unnessersary overhead of the Cache Object because you do not need
the things that the Cache Object offers you (like expiration, dependecies
and auto-remove), you just want to store a Object-Reference within memory.

You can use the SessionID as a key within the helper - property:

static class AsyncResultManager {

public static Dictionary<string, IAsyncResult> _dic = new ...();

public static IAsyncResult UserAsyncResult {
get{
return _dic[HttpContext.Current.Session.SessionID];
}

set{
_dic[HttpCOntext.Current.Session.SessionID] = value;
}

}

}



GP