ViewState is never saved during the callback
What I was trying to do here is to call a function from client, which will call "RaiseCallbackEvent", and I tried to stored the argument(from client) into viewstate. Yet, the viewState is never saved during the callback , why?

            public partial class _Default : System.Web.UI.Page, System.Web.UI.ICallbackEventHandler
            ....
            protected void Page_Load(object sender, EventArgs e)
            {

            ClientScriptManager cm = Page.ClientScript;
            String cbReference = cm.GetCallbackEventReference(this, "arg",
                "ReceiveServerData", "");
            String callbackScript = "function CallServer(arg, context) {" +
                cbReference + "; }";
            cm.RegisterClientScriptBlock(this.GetType(),
                "CallServer", callbackScript, true);
            }
           .....
           public void RaiseCallbackEvent(String eventArgument)
           {
               ViewState["attribute"] = eventArgument;
           }
           .....
ViewState is never saved during the callback
===

What I was trying to do here is to call a function from client, which will call "RaiseCallbackEvent", and I tried to stored the argument(from client) into viewstate. Yet, the viewState is never saved during the callback , why?

            public partial class _Default : System.Web.UI.Page, System.Web.UI.ICallbackEventHandler
            ....
            protected void Page_Load(object sender, EventArgs e)
            {

            ClientScriptManager cm = Page.ClientScript;
            String cbReference = cm.GetCallbackEventReference(this, "arg",
                "ReceiveServerData", "");
            String callbackScript = "function CallServer(arg, context) {" +
                cbReference + "; }";
            cm.RegisterClientScriptBlock(this.GetType(),
                "CallServer", callbackScript, true);
            }
           .....
           public void RaiseCallbackEvent(String eventArgument)
           {
               ViewState["attribute"] = eventArgument;
           }
           .....