C# - Prüfen ob aktueller Benutzer Administrator ist

using System.Security.Principal;

bool IsAnAdministrator ()
{
   WindowsIdentity  identity = 
      WindowsIdentity.GetCurrent();
   WindowsPrincipal principal = 
      new WindowsPrincipal (identity);
   return principal.IsInRole 
      (WindowsBuiltInRole.Administrator);
}