conditional format -- if not a date, then highlight cell

[laavista]

How do I enter a conditional format to highlight the cell if it's not a valid
date?

I tried "formula is":

=if(not isdate(C10))
<>if(isdate(C10))

Your help would be greatly appreciated!!

 

[Barb Reinhardt]

I think I'd put some data validation on the field to ensure that it's a date
as well.