XML сериализация

        public class GameState
        {
            public int Money { get; set; }
            public int Lives { get; set; }
        }

            GameState state = new GameState() // создаем объект с данными, базируясь на классе-шаблоне
            {
                Money = 1488,
                Lives = 228
            };

            XmlSerializer serializer = new XmlSerializer(typeof(GameState)); // создаем сериализатор и сообщаем ему о том, какой тип сериализуем
            using (TextWriter writer = new StreamWriter(@"C:\Users\Msey\Desktop\GameState.xml")) // если вкратце, то здесь мы создаем модуль, позволяющий записывать символы по указанной директории
            {
                serializer.Serialize(writer, state); // сериализуем данные
            }

<?xml version="1.0" encoding="utf-8"?>
<GameState xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
  <Money>1488</Money>
  <Lives>228</Lives>
</GameState>

        public class GameState
        {
            public int money;
            public int lives;
            private int weed;

            public GameState()
            {
                money = 1111;
                lives = 2222;
                weed  = 3333; // не будет сериализоваться, тк поле weed с модификатором доступа private
            }
        }

<?xml version="1.0" encoding="utf-8"?>
<GameState xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
  <money>1111</money>
  <lives>2222</lives>
</GameState>

            public GameState(int i =1111, int j =2222) // так нельзя - конструктор с параметрами
            {
                money = i;
                lives = j;
            }



            public GameState(int i , int j) // так тоже нельзя - конструктор продолжает быть параметрическим (Ваш кэп ©)
            {
                money = i;
                lives = j;
            }

        public class GameState
        {
            [XmlElement("no_money")] 
            public int money; // независимо от того, как называется поле, атрибут XmlElement указывает, что представляет элемент строкой ниже и сериализует/десериализует его под именем, указанном в этом атрибуте
            [XmlElement("no_lives")]
            public int lives;

            public GameState()
            {
                money = 1111;
                lives = 2222;
            }
        }

<?xml version="1.0" encoding="utf-8"?>
<GameState xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
  <no_money>1111</no_money>
  <no_lives>2222</no_lives>
</GameState>

[XmlElement(ElementName ="no_money", Namespace = "nmspc")]

<no_money xmlns="nmspc">1111</no_money>

        public class GameState
        {
            [XmlAttribute("MoneyAttribute")]
            public int money;

            [XmlAttribute("LivesAttribute")]
            public int lives;

            public GameState()
            {
                money = 2222;
                lives = 2222;
            }
        }

<?xml version="1.0" encoding="utf-8"?>
<GameState xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" MoneyAttribute="2222" LivesAttribute="2222" />

        public class GameState
        {
            [XmlIgnore]
            public int money;
            [XmlIgnore]
            public int lives;

            public GameState()
            {
                money = 1111;
                lives = 2222;
            }
        }

<?xml version="1.0" encoding="utf-8"?>
<GameState xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" />

        [XmlRoot("Root_GameState")]
        public class GameState
        {
            public int money;
            public int lives;

            public GameState()
            {
                money = 1111;
                lives = 2222;
            }
        }

<?xml version="1.0" encoding="utf-8"?>
<Root_GameState xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
  <money>1111</money>
  <lives>2222</lives>
</Root_GameState>

            GameState state;

            XmlSerializer deserializer = new XmlSerializer(typeof(GameState));

            using (TextReader reader = new StreamReader(@"C:\Users\Msey\Desktop\GameState.xml"))
            {
                state = (GameState) deserializer.Deserialize(reader);
            }

Json сериализация

            GameState state = new GameState();

            JsonSerializer serializer = new JsonSerializer();

            using (StreamWriter sw = new StreamWriter(@"C:\Users\Msey\Desktop\GameState.json"))
            using (JsonWriter writer = new JsonTextWriter(sw))
            {
                serializer.Serialize(writer, state);
            }

            GameState state;

            JsonSerializer serializer = new JsonSerializer();

            using (StreamReader sw = new StreamReader(@"C:\Users\Msey\Desktop\GameState.json"))
            using (JsonReader writer = new JsonTextReader(sw))
            {
                state = (GameState) serializer.Deserialize(writer);               
            }

Бинарная сериализация

            GameState state = new GameState();

            BinaryFormatter formatter = new BinaryFormatter();

            using (FileStream stream = new FileStream(@"C:\Users\Msey\Desktop\GameState.dat", FileMode.Create))
            {
                formatter.Serialize(stream, state);
            }

        [Serializable]
        public class GameState
        {
            public int money;
            public int lives;

            public GameState()
            {
                money = 1111;
                lives = 2222;
            }
        }

            GameState state;

            BinaryFormatter formatter = new BinaryFormatter();

            using (FileStream stream = new FileStream("C:\Users\Msey\Desktop\GameState.dat", FileMode.Open))
            {
                state = (GameState)formatter.Deserialize(stream);
            }