Should I Throw ArgumentNullException if a string is blank?

Question

I working on a method that does something given a string parameter. A valid value for the string parameter is anything other than null or string.Empty. So my code looks li

Answer 1

You should throw an ArgumentException if an empty string is not an accepted input for your method. It may be very confusing to clients if you throw an ArgumentNullException while they didn't provide a null argument.

It is simply another use case. You may also have methods that do not accept null input values but that do accept empty strings. It's important to be consistent across your entire application.