Default date in calendar

I have a calendar on a form in Visual Studio 2008 Express.  I have the default date set a page load to be today's date. The code is :
 protected void Page_Load(object sender, EventArgs e)         {             DateTime today = DateTime.Today;             Cal1.VisibleDate = Cal1.SelectedDate = today;
The only problem is that every time someone changes one of the other fields on the form, the date reverts to today.  Is there a way to have the date default to today on load but not change back with other field changes?

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