viewstate - so lost :(

Hello,
I will try to be quick and to the point. I have a calendar control who's DayRender event is used to query a database for events that match the day so that the background can be changed to a different color, *and* I add an entry to a dictionary<string,string> viewstate object... like:
((dictionary<string,string>)viewstate["dateToEventTracking"]).Add(e.Day.Date.Date.ToShortDateString(), sEventNameFromDB);
the viewstate object is first initialized on page_load in condition of *not* postback with something like:

Dictionary<string, string> DateToJobNumbers = new Dictionary<string, string>();             ViewState["DateToJobN ...