https://www.dotnetzone.gr:443/cs/blogs/napoleon/archive/2010/07/29/isnull-in-f.aspxA simple isNull for string functionality with Active Patterns 1 2 3 4 5 6 7 8 9 10 11 12 13 14 open System let (|Empty|Null|String|) (s: string ) = if s = null then Null elif s.Trim() |> String.IsNullOrEmpty then Empty else String (s.Trim()) let publicelCommunityServer 2.1 SP3 (Build: 20423.1)