術語(term):
1、序列化:序列化是將對象狀態轉換爲可保存或傳輸的格式的過程。
2、二進制序列化：二進制序列化保持類型保真度。
3、XML序列化，SOAP(Simple Object Access Protocol簡單對象訪問協議)序列化：XML序列化僅序列化公共屬性和字段，且不保持類型真度。
應用：可以將程序中的對象序列化到剪貼板、流文件、磁盤上等。這樣可以實現應用程序共享數據。比如遊戲存儲等。
.Net Framework提供兩種序列化技術：二進制序列化和XML序列化。
示例:
using System;
using System.Xml;
using System.Xml.Serialization;
using System.IO;
// The XmlRootAttribute allows you to set an alternate name
// (PurchaseOrder) for the XML element and its namespace. By
// default, the XmlSerializer uses the class name. The attribute
// also allows you to set the XML namespace for the element. Lastly,
// the attribute sets the IsNullable property, which specifies whether
// the xsi:null attribute appears if the class instance is set to
// a null reference.
[XmlRootAttribute("PurchaseOrder", Namespace = "http://www.cpandl.com",IsNullable = false)]
public class PurchaseOrder
{
public Address ShipTo;
public string OrderDate;
// The XmlArrayAttribute changes the XML element name
// from the default of "OrderedItems" to "Items".
[XmlArrayAttribute("Items")]
public OrderedItem[] OrderedItems;
public decimal SubTotal;
public decimal ShipCost;
public decimal TotalCost;
}
public class Address
{
// The XmlAttribute instructs the XmlSerializer to serialize the
// Name field as an XML attribute instead of an XML element (the
// default behavior).
[XmlAttribute]
public string Name;
public string Line1;
// Setting the IsNullable property to false instructs the
// XmlSerializer that the XML attribute will not appear if
// the City field is set to a null reference.
[XmlElementAttribute(IsNullable = false)]
public string City;
public string State;
public string Zip;
}
public class OrderedItem
{
public string ItemName;
public string Description;
public decimal UnitPrice;
public int Quantity;
public decimal LineTotal;
// Calculate is a custom method that calculates the price per item
// and stores the value in a field.
public void Calculate()
{
LineTotal = UnitPrice * Quantity;
}
}
public class Test
{
public static void Main()
{
// Read and write purchase orders.
Test t = new Test();
t.CreatePO("po.xml");
t.ReadPO("po.xml");
Console.ReadLine();
}
private void CreatePO(string filename)
{
// Creates an instance of the XmlSerializer class;
// specifies the type of object to serialize.
XmlSerializer serializer = new XmlSerializer(typeof(PurchaseOrder));
TextWriter writer = new StreamWriter(filename);
PurchaseOrder po = new PurchaseOrder();
// Creates an address to ship and bill to.
Address billAddress = new Address();
billAddress.Name = "Teresa Atkinson";
billAddress.Line1 = "1 Main St.";
billAddress.City = "AnyTown";
billAddress.State = "WA";
billAddress.Zip = "00000";
// Sets ShipTo and BillTo to the same addressee.
po.ShipTo = billAddress;
po.OrderDate = System.DateTime.Now.ToLongDateString();
// Creates an OrderedItem.
OrderedItem i1 = new OrderedItem();
i1.ItemName = "Widget S";
i1.Description = "Small widget";
i1.UnitPrice = (decimal)5.23;
i1.Quantity = 3;
i1.Calculate();
// Inserts the item into the array.
OrderedItem[] items = { i1 };
po.OrderedItems = items;
// Calculate the total cost.
decimal subTotal = new decimal();
foreach (OrderedItem oi in items)
{
subTotal += oi.LineTotal;
}
po.SubTotal = subTotal;
po.ShipCost = (decimal)12.51;
po.TotalCost = po.SubTotal + po.ShipCost;
// Serializes the purchase order, and closes the TextWriter.
serializer.Serialize(writer, po);
writer.Close();
}
protected void ReadPO(string filename)
{
// Creates an instance of the XmlSerializer class;
// specifies the type of object to be deserialized.
XmlSerializer serializer = new XmlSerializer(typeof(PurchaseOrder));
// If the XML document has been altered with unknown
// nodes or attributes, handles them with the
// UnknownNode and UnknownAttribute events.
serializer.UnknownNode += new XmlNodeEventHandler(serializer_UnknownNode);
serializer.UnknownAttribute += new XmlAttributeEventHandler(serializer_UnknownAttribute);
// A FileStream is needed to read the XML document.
FileStream fs = new FileStream(filename, FileMode.Open);
// Declares an object variable of the type to be deserialized.
PurchaseOrder po;
// Uses the Deserialize method to restore the object's state
// with data from the XML document. */
po = (PurchaseOrder)serializer.Deserialize(fs);
// Reads the order date.
Console.WriteLine("OrderDate: " + po.OrderDate);
// Reads the shipping address.
Address shipTo = po.ShipTo;
ReadAddress(shipTo, "Ship To:");
// Reads the list of ordered items.
OrderedItem[] items = po.OrderedItems;
Console.WriteLine("Items to be shipped:");
foreach (OrderedItem oi in items)
{
Console.WriteLine("/t" +
oi.ItemName + "/t" +
oi.Description + "/t" +
oi.UnitPrice + "/t" +
oi.Quantity + "/t" +
oi.LineTotal);
}
// Reads the subtotal, shipping cost, and total cost.
Console.WriteLine(
"/n/t/t/t/t/t Subtotal/t" + po.SubTotal +
"/n/t/t/t/t/t Shipping/t" + po.ShipCost +
"/n/t/t/t/t/t Total/t/t" + po.TotalCost
);
}
protected void ReadAddress(Address a, string label)
{
// Reads the fields of the Address.
Console.WriteLine(label);
Console.Write("/t" + a.Name + "/n/t" + a.Line1 + "/n/t" + a.City + "/t" + a.State + "/n/t" + a.Zip + "/n");
}
protected void serializer_UnknownNode(object sender, XmlNodeEventArgs e)
{
Console.WriteLine("Unknown Node:" + e.Name + "/t" + e.Text);
}
protected void serializer_UnknownAttribute(object sender, XmlAttributeEventArgs e)
{
System.Xml.XmlAttribute attr = e.Attr;
Console.WriteLine("Unknown attribute " + attr.Name + "='" + attr.Value + "'");
}
}
//XML 輸出可能如下：
//<?xml version="1.0" encoding="utf-8"?>
//<PurchaseOrder xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns="http://www.cpandl.com">
// <ShipTo Name="Teresa Atkinson">
// <Line1>1 Main St.</Line1>
// <City>AnyTown</City>
// <State>WA</State>
// <Zip>00000</Zip>
// </ShipTo>
// <OrderDate>Wednesday, June 27, 2001</OrderDate>
// <Items>
// <OrderedItem>
// <ItemName>Widget S</ItemName>
// <Description>Small widget</Description>
// <UnitPrice>5.23</UnitPrice>
// <Quantity>3</Quantity>
// <LineTotal>15.69</LineTotal>
// </OrderedItem>
// </Items>
// <SubTotal>15.69</SubTotal>
// <ShipCost>12.51</ShipCost>
// <TotalCost>28.2</TotalCost>
//</PurchaseOrder>