c# - Visual Studio 2003 can't navigate to the definition of "IIdentity" or "StringTable" -

i have following code:

using system; using system.collections; using system.security; using system.security.principal;  public class systemprincipal : iprincipal {      private iidentity       _identity;     private stringtable     _roles;      public systemprincipal(iidentity id, stringtable roles) {          _identity = id;         _roles = roles;;     }      public iidentity identity {          { return _identity; }     }      public bool isinrole(string role) {          bool result = false;          if (null != _roles) {             result = _roles.contains(role);         }         return result;                   } } 

i want see definition of iidentity or stringtable right click , choose goto definition "cannot naviate to" iidentity or stiringtable.

based on google soultion rebuilt project did not solve issue.