c# Serialize的簡單範例 & binary和xml存檔方式比較 



C# 的Serialize功能能讓我們很容易的幫自訂類別進行存檔
一般Serialize有2種作法 一種是存成binary 一種是存成xml
網路上的範例都太複雜了 基本的作法如下 幾行程式碼而已
首先 當然你的class要有[Serializable]的標籤

ex:
[Serializable]
public class myclass
{
 public string text;
 public int number;
 public float number2;
 public myclass()
 {
 text = "abc";
 number = 3;
 number2 = 12.34;
 }
}
myclass myobj=new myclass();

然後兩種作法的讀寫範例程式碼如下 看你是要存成binary還是存成xml:

binary存檔

IFormatter binFmt = new BinaryFormatter();
Stream s = File.Open("binary存檔檔名", FileMode.Create);
binFmt.Serialize(s, myobj);
s.Close();

binary讀檔

IFormatter binFmt = new BinaryFormatter();
Stream s = File.Open("binary存檔檔名", FileMode.Open);
myobj = (myclass)binFmt.Deserialize(s);
s.Close();

------

xml存檔

System.Xml.Serialization.XmlSerializer ser = new System.Xml.Serialization.XmlSerializer(myobj.GetType()); 
Stream s = File.Open("xml存檔檔名", FileMode.Create);
ser.Serialize(s, myobj);
s.Close();

xml讀檔

System.Xml.Serialization.XmlSerializer ser = new System.Xml.Serialization.XmlSerializer(myobj.GetType()); 
Stream s = File.Open("xml存檔檔名", FileMode.Open);
myobj = (myclass)ser.Deserialize(s);
s.Close();

======

binary和xml存檔方式的比較

binary較省空間 但可維護性較差 移植性也比較差 存檔只能由程式開啟
若遺失了原始的class定義 資料很難parse回來 因為是二進位格式
而xml存檔格式較通用 即使本來的程式遺失了仍然可透過xml parser把存檔中的子元素救回來
使用者也可直接透過記事本或xml editer編輯存檔裡的元素 不需透過特定程式
但是xml檔案所佔容量較大 且並非所有.NET原生物件都能存成xml
某些型別在Serialize成xml時會有問題
例如Font , Color等高階型別只能由binary寫入 透過XML方式寫入會產生執行時期錯誤
(這方面應該是.NET函式庫沒做好 技術上來說那些高階型別存成xml並不是不可能 或許有其他原因是我不知道的)

----------
result from serializable class belows:

<?xml version="1.0"?>
<Garage xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
  <GarageOwner>John</GarageOwner>
  <MyVehicles>
    <Vehicle>
      <VehicleType>Car</VehicleType>
      <VehicleNumber>1234</VehicleNumber>
    </Vehicle>
    <Vehicle>
      <VehicleType>Boat</VehicleType>
      <VehicleNumber>56234</VehicleNumber>
    </Vehicle>
  </MyVehicles>
</Garage>
----------
sample first:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO;
using System.Xml;
using System.Xml.Serialization;

namespace Patterns
{
    [Serializable()]
    public class Garage
    {
        private Vehicle _MyVehicle;

        public Garage()
        {
        }
        public string GarageOwner { get; set; }
        public Vehicle MyVehicle
        {
            get { return _MyVehicle; }
            set { _MyVehicle = value; }
        }
    }

    [Serializable()]
    public class Vehicle
    {
        public string VehicleType { get; set; }
        public int VehicleNumber { get; set; }
    }

    class Serializer
    {
        static string _StartupPath = @"C:\Projects\Patterns\Data\";
        static string _StartupFile = "SerializerTest.xml";
        static string _StartupXML = _StartupPath + _StartupFile;

        static void Main(string[] args)
        {
            Console.Write("Press w for write. Press r for read:");
            ConsoleKeyInfo cki = Console.ReadKey(true);
            Console.WriteLine("Pressed: " + cki.KeyChar.ToString());
            if (cki.KeyChar.ToString() == "w")
            {
                Garage MyGarage = new Garage();
                MyGarage.GarageOwner = "John";
                MyGarage.MyVehicle = new Vehicle();
                MyGarage.MyVehicle.VehicleType = "Car";
                MyGarage.MyVehicle.VehicleNumber = 1234;
                WriteGarageXML(MyGarage);
                Console.WriteLine("Serialized");
            }
            else if (cki.KeyChar.ToString() == "r")
            {
                Garage MyGarage = ReadGarageXML();
                Console.WriteLine("Deserialized Garage owned by " +  MyGarage.GarageOwner);
            }
            Console.ReadKey();
        }
        public static void WriteGarageXML(Garage pInstance)
        {
            XmlSerializer writer = new XmlSerializer(typeof(Garage));
            using (FileStream file = File.OpenWrite(_StartupXML))
            {
                writer.Serialize(file, pInstance);
            }
        }
        public static Garage ReadGarageXML()
        {
            XmlSerializer reader = new XmlSerializer(typeof(Garage));
            using (FileStream input = File.OpenRead(_StartupXML))
            {
                return reader.Deserialize(input) as Garage;
            }
        }
    }
}

----------
sample last:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO;
using System.Xml;
using System.Xml.Serialization;

namespace Patterns
{
    public class Garage
    {
        private Vehicle _MyVehicle;

        public Garage()
        {
        }
        public string GarageOwner { get; set; }

        public Vehicle MyVehicle
        {
            get { return _MyVehicle; }
            set { _MyVehicle = value; }
        }
    }

    [XmlInclude(typeof(Car))]
    [XmlInclude(typeof(Boat))]
    [XmlInclude(typeof(Motorcycle))]
    [XmlInclude(typeof(Motorhome))]
    public abstract class Vehicle
    {
        public string VehicleType { get; set; }
        public int VehicleNumber { get; set; }
    }
    public class Car : Vehicle
    {
        public int Doors { get; set; }
    }
    public class Boat : Vehicle
    {
        public int Engines { get; set; }
    }
    public class Motorcycle : Vehicle
    {
        public int Wheels { get; set; }
    }
    public class Motorhome : Vehicle
    {
        public int Length { get; set; }
    }

    class Serializer
    {
        static string _StartupPath = @"C:\Projects\Patterns\Data\";
        static string _StartupFile = "SerializerTest.xml";
        static string _StartupXML = _StartupPath + _StartupFile;

        static void Main(string[] args)
        {
            Console.Write("Press w for write. Press r for read:");
            ConsoleKeyInfo cki = Console.ReadKey(true);
            Console.WriteLine("Pressed: " + cki.KeyChar.ToString());
            if (cki.KeyChar.ToString() == "w")
            {
                Garage MyGarage = new Garage();
                MyGarage.GarageOwner = "John";
                Car c = new Car();
                c.VehicleType = "Lexus";
                c.VehicleNumber = 1234;
                c.Doors = 4;
                MyGarage.MyVehicle = c;
                WriteGarageXML(MyGarage);
                Console.WriteLine("Serialized");
            }
            else if (cki.KeyChar.ToString() == "r")
            {
                Garage MyGarage = ReadGarageXML();
                Console.WriteLine("Deserialized Garage owned by " + MyGarage.GarageOwner);
            }
            Console.ReadKey();
        }
        public static void WriteGarageXML(Garage pInstance)
        {
            XmlSerializer writer = new XmlSerializer(typeof(Garage));
            using (FileStream file = File.OpenWrite(_StartupXML))
            {
                writer.Serialize(file, pInstance);
            }
        }
        public static Garage ReadGarageXML()
        {
            XmlSerializer reader = new XmlSerializer(typeof(Garage));
            using (FileStream input = File.OpenRead(_StartupXML))
            {
                return reader.Deserialize(input) as Garage;
            }
        }
    }    
}