How to validate non-required fields?

[Tien]

Hi,

By default, all controls must have a RequiredField control in order to
use more complex validation control e.g. RangeValidator, so how can I
use validation controls with non-required fields?

Thanks,

 

[Martin Dechev]

Hi,

If there is some input in the control it will be validated against the
RangeValidator with or without RequiredFieldValidator. If there is no input
the RangeValidator (or RegularExpressionValidator) will judge the input as
valid, that's why one normally uses it in combination with a
RequiredFieldValidator. RequiredFieldValidator only ensures that there is
input. Validators work independant from each other.

Hope this helps
Martin Dechev
ASP.NET MVP