https://www.dotnetzone.gr:443/cs/blogs/birbilis/archive/2013/03/26/net-string-class-extensions-to-replace-prefix-or-suffix.aspxJust added the following extension methods to StringExtensions class (of Utils.Extensions namespace) under Utils.Silverlight project at the ClipFlair source code. public static string ReplacePrefix( this string s, string fromPrefix, string toPrefix, StringComparisonelCommunityServer 2.1 SP3 (Build: 20423.1)