A code has 3 components - represented as members:

• A coding scheme
• A code value
• A code representation (the human readable form)

For more details on use of codes see : Use of Codes in XDS:

System.Object
   XdsObjects.XdsCode

Target Platforms: Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

Reference

XdsCode Members
XdsObjects Namespace