Microsoft® Windows® Workflow Foundation Step by Step

Building Your First Workflow Program

Here is a small code snippet that performs postal code validation, and it’s one you’ve no doubt written before or probably very much like one you would write if asked to do so:

protected const string USCode =
   @"^(\d{5}$)|(\d{5}$\-\d{4}$)";
protected const string CanadianCode =
   @"[ABCEGHJKLMNPRSTVXY]\d[A-Z] \d[A-Z]\d";

public static bool ValidatePostalCode(string str)
{
   return (Regex.IsMatch(str, USCode) ||
           Regex.IsMatch(str, CanadianCode));
}

Nothing special here—"Test the input string against a properly formatted US ZIP code or Canadian postal code and return false if improperly formatted for either postal system." It’s a nice chunk of procedural code, and in fact you could drop it into your ASP.NET validation ...