Parsing multivalued SharePoint fields with Regex

As Mark Arend points out on his blog, there are quite a number of ways SharePoint formats complex field values. His list even misses the Lookup multiple values variant that e.g. can be: "Kategori 2;#1;#Kategori 1".

To split the composite fields we need a little regular expression fission:

readonly static Regex _regex = new Regex(
  @"([\#]?(\d+;\#)?)?(?'item'[^;]+)(\#?)",
  RegexOptions.ExplicitCapture | RegexOptions.Compiled | RegexOptions.CultureInvariant);

static IEnumerable<string> SplitsAnySPMultiValueField(string value)
{
  return _regex.Matches(value).Cast<Match>()
         .Select(match => match.Groups["item"].Value);
}

Here is a list of examples.

The Hyperlink/Picture field value is comma separated, and I didn't want to split any text containing a comma, so that one is another story.