c# nameof

                var i = 100;
                switch (i)
                {
                    case int code when code >= 500:
                        break;
                }
                byte[] cipherText; 
                byte[] Key;
                var s1 = nameof(cipherText);
                var s2 = nameof(Key);

            if (!DateTime.TryParse(applicationDatetime.ToString(), out DateTime _))
            {
            }