Question

Trying to create a regex for Date in this format dd.MM.yyyy.

I want to use it with a DataAnnotation, like this

[RegularExpression(@"<theregex>")]
public DateTime Date { get; set; }

Answer 1

I suggest that regex is not exactly the best way to do this. You haven’t given the context, so it’s hard to guess what you’re doing overall… but you might want to create a DateExpression attribute or such and then do:

return DateTime.ParseExact(value, "dd.MM.yyyy");

in wherever your converter is defined.