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c#regex.net-3.5

Is it possible for Regex.Match() to return null? (C# .Net framework 3.5?)

Is it possible that regex.Match in the (much simplified) code below can ever return null?

Regex regex = new Regex(pattern);
Match m = regex.Match(input);

My static analysis tool complains without a null check on m, but I'm thinking it's not actually necessary. It'd be nice to remove the null check so my code coverage is 100% for the method it's contained in.

Solution

  • Documentation is your friend here:

    Return Value

    Type: System.Text.RegularExpressions.Match

    An object that contains information about the match.

    Microsoft is telling you that it will only return a Match object (not null), which means you can rightfully assume this to be true.

    There is a chance, according to the docs, that it throws an exception (ArgumentNullException or RegexMatchTimeoutException), though.

    What you want to check, is the returned Match's Success property.