How do I persist session values in ASP.NET?

I'm implementing IHttpHandler and IRequiresSessionState and I'm using context.Session but after I set up a value in Session, it's lost in the next request. What can I do to persist the values ?

$.ajax({
        url: "/test.test", 
        type: "POST",
        data: "{'type':'GetStep'}",
        contentType: "application/json; charset=utf-8",
        dataType: "json",
        success: function (result) {...}
 });

The second call is similar to this, but the values that get set when I call this function are also lost on the next request.

public void ProcessRequest (HttpContext context)
{
开发者_Go百科    context.Session ["Game"] = new Game (); // next time it is null
}

How do I persist values in Session state in ASP.NET ?

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Do you have session state defined in your web.config? Something like this

<sessionState mode="InProc" stateConnectionString="tcpip=127.0.0.1:42424" sqlConnectionString="data source=127.0.0.1;Trusted_Connection=yes" cookieless="false" timeout="20"/>