No Date Passed

I want to update a record that has a datetime field in it. But what if there is no parameter given for that field, i.e. what is the correct type/value to pass as parameter?





Example: A DOB field for a user profile, but the user doesn't enter his birthday





This is some example code that I use to update:





Private Sub UpdateDOB(ByVal dob As Date)





Dim parameters As SqlParameter() = { _


New SqlParameter("@Birthday", SqlDbType.DateTime, 8)}





parameters(0).Value = dob





'Run Stored Procedure





This gives me the exception "SqlDateTime overflow. Must be between 1/1/1753 12:00:00 AM and 12/31/9999 11:59:59 PM" when I don't pass a valid date. I tried passing Nothing but same error (in this case it convert dob to "#12:00:00 AM#")





The only thing I can think of is to use Date.MaxValue and then check in application logic, but there must be a better way!