System.AppDomain.SetThreadPrincipal C# (CSharp) Method

        public void SetThreadPrincipal(IPrincipal principal)
        {
            if (principal == null)
            {
                throw new ArgumentNullException(nameof(principal));
            }

            lock (_forLock)
            {
                // Check that principal has not been set previously.
                if (_defaultPrincipal != null)
                {
                    throw new SystemException(SR.AppDomain_Policy_PrincipalTwice);
                }
                _defaultPrincipal = principal;
            }
        }

		public void SetThreadPrincipal () 
		{
			IIdentity i = new GenericIdentity ("*****@*****.**", "rfc822");
			IPrincipal p = new GenericPrincipal (i, null);
			ad = AppDomain.CreateDomain ("SetThreadPrincipal");
			ad.SetThreadPrincipal (p);
		}