is it possible to run async call to set a session in ASP.NET?

I have a page that access Database running a heavy stored procedure and return a result, th开发者_StackOverflowe result will be displayed depending on a session variable Session["isShown"] for example.

I would like to using Ajax to call another page to set :

 xmlhttp.open("POST", "frmCancelWfSearch.aspx", true);
 xmlhttp.send();

how to run frmCancelWfSearch.aspx asynchrounously to set that Session["isShown"] to false?

Implement your server code in an IHttpAsyncHandler and also implement IRequiresSessionState so you have access to the session.

http://msdn.microsoft.com/en-us/magazine/cc164128.aspx

You can use query string parameter say isshow=true or isshow=false and in your frmCancelWfSearch.aspx depending on the value of this parameter you can change the value of your session variable. You can send query string params when using POST like this: xmlHttp.send("isshow=false");