Hi.
For your problem, you will want to use ParseExact to convert the string.
There are many examples on this on the forum.
Basically, it would look like this:
Date.ParseExact("14.06.2018", "dd.MM.yyyy", System.Globalization.CultureInfo.CurrentCulture)
EDIT: had a typo
This will only work if the string is in the format that you specify, “dd.MM.yyyy”. So, you will need to maybe surround this by a Try/Catch for times when the string is not a date.
Once it is in a DateTime type you can check the value by using:
yourdatevariable >= Now
et cetera…
Regards.