編寫高質量代碼改善C#程序的157個建議——建議57：實現ISerializable的子類型應負責父類的序列化，

編寫高質量代碼改善C#程序的157個建議——建議57：實現ISerializable的子類型應負責父類的序列化，

建議57：實現ISerializable的子類型應負責父類的序列化

我們將要實現的繼承自ISerializable的類型Employee有一個父類Person，假設Person沒有實現序列化，而現在子類Employee卻需要滿足序列化的場景。不過序列化器並沒有默認處理Person類型對象，這些事情只能由我們自己做。

以下是一個不妥的實現，序列化器只發現和處理了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);
        }
    }    

序列化工具類：

public class BinarySerializer { //將類型序列化為字符串 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()); } } //將類型序列化為文件 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(); } } //將字符串反序列化為類型 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; } } //將文件反序列化為類型 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

輸出為：

姓名：
薪水：2000

看見，Name字段並沒有正確處理。這需要我們修改類型Employee中受保護的構造方法GetObjectData方法，為它加入父類字段的處理：

    [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);
        }
    } 

修改後輸出：

姓名：liming
薪水：2000

上面的例子中Person類未被設置成支持序列化。現在，假設Person類已經實現了ISerializable接口，那麼這個問題處理起來會相對容易，在子類Employee中，我們只需要調用父類受保護的構造方法和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);
        }
    }

 

 

 

 

轉自：《編寫高質量代碼改善C#程序的157個建議》陸敏技