calendar control question

Hello,
I'm using a standard .net calendar control on as asp.net webform. I'm using the DayRender event to get data from a database... currently, if one or more data matches are found for the day, I set the backcolor of the table cell, and set it's tooltip with relevant data from the data record. Now I need to handle the selectionChanged event and I need access to the data that was used in the DayRender event... I realize I can use the calendar's selectedDate property and re-query the database to get the data again, but I wanted to check to see if there are alternatives, and save the extra trip to the database. Is there something I can do in the DayRender event that will persist this data so that it gets passed to, or is available from the SelectionChanged event?
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