db error

[EyeTalion]

I have an update page where the user can change data in the db. When I delete data from a textbox and keep it empty, then save to the db, I get this error:

String was not recognized as a valid DateTime.

Is there a way around this?
thanks

[Cander]

you cannot have blank values in a DateTime field.

[EyeTalion]

in the database it can be null. How do I insert a null value into that field?

[mpSmooth]

DbNull.Value