System.Globalization Namespace
Maps strings to their sort keys.
Each character in a string is given several categories of sort weights, including script, alphabetic, case, and diacritic weights. A sort key serves as the repository of these weights for a particular string. For example, a sort key might contain a string of alphabetic weights, followed by a string of case weights, and so on. SortKey is equivalent to the Windows API method LCMapString with the LCMAP_SORTKEY flag.