Is there way in .NET to check that a particular instance of a string matches a given format string? So say my format string is "Hello, {0}!" and I have "Hello, World!", to use an old cliched example, I'm looking for a comparison method that will return true when comparing these. I know I could write a String extension method for doing this but just want to make sure I'm not about to reinvent the wheel...

If anyone's interested, the reason I'm asking is because I'm writing an NUnit test to verify a message being displayed to the user but I don't know or care what the code inserts into the params for the format string, I just want to check that it uses it.