编写高质量代码改进C#程序的157个建议——建议57：实现ISerializable的子类型应负责父类的序列化_C#

编写高质量代码改善C#程序的157个建议——建议57：实现ISerializable的子类型应负责父类的序列化

建议57：实现ISerializable的子类型应负责父类的序列化

我们将要实现的继承自ISerializable的类型Employee有一个父类Person，假设Person没有实现序列化，而现在子类Employee却需要满足序列化的场景。不过序列化器并没有默认处理Person类型对象，这些事情只能由我们自己做。

以下是一个不妥的实现，序列化器只发现和处理了Employee中Salary字段：

    class Program    {        static void Main()        {            Employee  liming = new Employee() { Name = "liming", Salary = 2000 };            BinarySerializer.SerializeToFile(liming, @"c:\", "person.txt");            Employee limingCopy = BinarySerializer.DeserializeFromFile<Employee>(@"c:\person.txt");            Console.WriteLine(string.Format("姓名：{0}", limingCopy.Name));            Console.WriteLine(string.Format("薪水：{0}", limingCopy.Salary));        }    }        public class Person    {        public string Name { get; set; }    }    [Serializable]    public class Employee : Person, ISerializable    {        public int Salary { get; set; }        public Employee()        {        }        protected Employee(SerializationInfo info, StreamingContext context)        {            Salary = info.GetInt32("Salary");        }        public override void GetObjectData(SerializationInfo info, StreamingContext context)        {            info.AddValue("Salary", Salary);        }    }

序列化工具类：

    public class BinarySerializer    {        //将类型序列化为字符串        public static string Serialize<T>(T t)        {            using (MemoryStream stream = new MemoryStream())            {                BinaryFormatter formatter = new BinaryFormatter();                formatter.Serialize(stream, t);                return System.Text.Encoding.UTF8.GetString(stream.ToArray());            }        }        //将类型序列化为文件        public static void SerializeToFile<T>(T t, string path, string fullName)        {            if (!Directory.Exists(path))            {                Directory.CreateDirectory(path);            }            string fullPath = Path.Combine(path, fullName);            using (FileStream stream = new FileStream(fullPath, FileMode.OpenOrCreate))            {                BinaryFormatter formatter = new BinaryFormatter();                formatter.Serialize(stream, t);                stream.Flush();            }        }        //将字符串反序列化为类型        public static TResult Deserialize<TResult>(string s) where TResult : class        {            byte[] bs = System.Text.Encoding.UTF8.GetBytes(s);            using (MemoryStream stream = new MemoryStream(bs))            {                BinaryFormatter formatter = new BinaryFormatter();                return formatter.Deserialize(stream) as TResult;            }        }        //将文件反序列化为类型        public static TResult DeserializeFromFile<TResult>(string path) where TResult : class        {            using (FileStream stream = new FileStream(path, FileMode.Open))            {                BinaryFormatter formatter = new BinaryFormatter();                return formatter.Deserialize(stream) as TResult;            }        }    }

View Code

输出为：

姓名：
薪水：2000

看见，Name字段并没有正确处理。这需要我们修改类型Employee中受保护的构造方法GetObjectData方法，为它加入父类字段的处理：

    [Serializable]    public class Employee : Person, ISerializable    {        public int Salary { get; set; }        public Employee()        {        }        protected Employee(SerializationInfo info, StreamingContext context)        {            Name = info.GetString("Name");            Salary = info.GetInt32("Salary");        }        public void GetObjectData(SerializationInfo info, StreamingContext context)        {            info.AddValue("Name", Name);            info.AddValue("Salary", Salary);        }    }

修改后输出：

姓名：liming
薪水：2000

上面的例子中Person类未被设置成支持序列化。现在，假设Person类已经实现了ISerializable接口，那么这个问题处理起来会相对容易，在子类Employee中，我们只需要调用父类受保护的构造方法和GetObjectData方法就可以了。如下所示：

    [Serializable]    public class Person : ISerializable    {        public string Name { get; set; }        public Person()        {        }        protected Person(SerializationInfo info, StreamingContext context)        {            Name = info.GetString("Name");        }        public virtual void GetObjectData(SerializationInfo info, StreamingContext context)        {            info.AddValue("Name", Name);        }    }    [Serializable]    public class Employee : Person, ISerializable    {        public int Salary { get; set; }        public Employee()        {        }        protected Employee(SerializationInfo info, StreamingContext context)            : base(info, context)        {            Salary = info.GetInt32("Salary");        }        public override void GetObjectData(SerializationInfo info, StreamingContext context)        {            base.GetObjectData(info, context);            info.AddValue("Salary", Salary);        }    }

转自：《编写高质量代码改善C#程序的157个建议》陆敏技