What is wrong with DateTime.Parse(myString)?

Question

I was browsing Scott Hanselman's Developer Interview question list, and ran across this question:

What is wrong with DateTime.Parse(myString)?

While I know there are inherent risks in parsing a string of unknow format or origin, are there other reasons? Is it to use DateTime.ParseExact instead? Should it be myString.ToString() first?

Answer 1

In addition the locale problem, DateTime.Parse() could also throw an exception which you would then have to catch. Use DateTime.TryParse() or DateTime.TryParseExact() instead.

Answer 2

Using the current thread culture on the system is often a bad idea, as is "try a variety of formats, and see if any of them work."

ParseExact with a specific culture is a much more controlled and precise approach. (Even if you specify the current culture, it makes it more obvious to readers that that's what's going on.)

Answer 3

As MSDN Puts it:

Because the Parse(String) method tries to parse the string representation of a date and time using the formatting rules of the current culture, trying to parse a particular string across different cultures can either fail or return different results. If a specific date and time format will be parsed across different locales, use the DateTime.Parse(String, IFormatProvider) method or one of the overloads of the ParseExact method and provide a format specifier.