你的位置:首页 > ASP.net教程

[ASP.net教程]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