IsAdmin

Here’s how you can determine if the current user is an administrator from a C# program:

static bool IsAdmin () {
  AppDomain.CurrentDomain.SetPrincipalPolicy (PrincipalPolicy.WindowsPrincipal);
  WindowsPrincipal principal = (WindowsPrincipal)Thread.CurrentPrincipal;
  return principal.IsInRole (WindowsBuiltInRole.Administrator);
}