序列化，是将对象状态转换为可保持或传输的格式的过程。

与序列化相反的是反序列化，它将流转换为对象。这两个过程结合起来，就可以存储和传输数据。这就是序列化的意义所在。

在VB.NET中转换、处理和生成XML文档时，需要用到一些XML专用名称空间中的类，这些名称空间包括：

System.Xml 该名称空间提供了对各种XML标准（包括DTD、名称空间、DOM、XDR（XML Data Reduced，XML架构标准的旧版本）、XPath、XSLT和SOAP（以前表示Simple Object Access Protocol标准，现在什么也不表示））的核心支持。

System.Xml.Serialization 该名称空间提供的对象使用序列化技术进行对象与XML文档或流之间的转换。

System.Xml.Schema 该名称空间提供一组用于加载、创建和输出架构的对象，这些对象可以在内存中操作组成XML架构的各种实体

System.Xml.Xpath 该名称空间为XPath（XML Path Language）提供语法分析程序和估算引擎。

System.Xml.Xsl 该名称空间提空了使用XSL（Extensible Stylesheet Language）和XSLT（XSL Transformation）时必须用到的对象。

今天我想讨论的是VB.NET反序列化XML。

以下是我想反序列化的XML的结构：

<card>
	<sCodeBorder y1='34' y2='120' x2='568' x1='360' />
	<border y1='0' y2='1008' x2='1650' x1='0' />
	<area>
		<question id='1' x1='70' y1='274' x2='180' y2='288' >
			<option id='A' x1='70' y1='274' x2='90' y2='288' />
		</question>
		<question id='2' x1='70' y1='298' x2='180' y2='312' >
			<option id='A' x1='70' y1='298' x2='90' y2='312' />
			<option id='B' x1='100' y1='298' x2='120' y2='312' />
		</question>
		<question id='3' x1='70' y1='322' x2='180' y2='336' >
			<option id='A' x1='70' y1='322' x2='90' y2='336' />
			<option id='B' x1='100' y1='322' x2='120' y2='336' />
			<option id='C' x1='130' y1='322' x2='150' y2='336' />
		</question>
	</area>
</card>

我们首先要做的是创建与XML相对应的对象，然后再把XML转换成我们想要的对象。

创建的类中需要引用System.Xml.Serialization 命名空间。这一命名空间包含用于将对象序列化为XML格式文档或流的类。

Public Class card
    <XmlElementAttribute("sCodeBorder")> Public sCodeBorder As sCodeBorder
    <XmlElementAttribute("border")> Public border As border
    <XmlElementAttribute("area")> Public area As area

    Public Sub New()
    End Sub

    Public Sub New(ByVal sCodeBorder As sCodeBorder,ByVal border As border,ByVal area As area )
        Me.sCodeBorder = sCodeBorder
        Me.border = border
        Me.area = area
    End Sub
End Class

Public Class sCodeBorder
    <XmlAttributeAttribute("x1")> Public x1 As Integer
    <XmlAttributeAttribute("x2")> Public x2 As Integer
    <XmlAttributeAttribute("y1")> Public y1 As Integer
    <XmlAttributeAttribute("y2")> Public y2 As Integer

    Public Sub New()
    End Sub
    Public Sub New(ByVal x1 As Integer,ByVal x2 As Integer,ByVal y1 As Integer,ByVal y2 As Integer)
        Me.x1 = x1
        Me.x2 = x2
        Me.y1 = y1
        Me.y2 = y2
    End Sub
End Class

Public Class border
    <XmlAttributeAttribute("x1")> Public x1 As Integer
    <XmlAttributeAttribute("x2")> Public x2 As Integer
    <XmlAttributeAttribute("y1")> Public y1 As Integer
    <XmlAttributeAttribute("y2")> Public y2 As Integer

    Public Sub New()
    End Sub
    Public Sub New(ByVal x1 As Integer,ByVal y2 As Integer)
        Me.x1 = x1
        Me.x2 = x2
        Me.y1 = y1
        Me.y2 = y2
    End Sub
End Class

Public Class area
    <XmlElementAttribute("question")> Public Ques_List() As question
    Public Sub New()
    End Sub

    Public Sub New(ByVal multiQ() As question)
        Me.Ques_List = multiQ
    End Sub
End Class

Public Class question
    <XmlAttributeAttribute("x1")> Public x1 As Integer
    <XmlAttributeAttribute("x2")> Public x2 As Integer
    <XmlAttributeAttribute("y1")> Public y1 As Integer
    <XmlAttributeAttribute("y2")> Public y2 As Integer
    <XmlAttributeAttribute("id")> Public id As String
    <XmlElementAttribute("option")> Public multiOptions_List() As option_
    Public Sub New()
    End Sub

    Public Sub New(ByVal x1 As Integer,ByVal y2 As Integer,ByVal id As String,ByVal multiO() As option_)
        Me.x1 = x1
        Me.x2 = x2
        Me.y2 = y2
        Me.y1 = y1
        Me.id = id
        Me.multiOptions_List = multiO
    End Sub
End Class

Public Class option_
    <XmlAttributeAttribute("x1")> Public x1 As Integer
    <XmlAttributeAttribute("x2")> Public x2 As Integer
    <XmlAttributeAttribute("y1")> Public y1 As Integer
    <XmlAttributeAttribute("y2")> Public y2 As Integer
    <XmlAttributeAttribute("id")> Public id As String

    Public Sub New()
    End Sub

    Public Sub New(ByVal x1 As Integer,ByVal id As String)
        Me.x1 = x1
        Me.x2 = x2
        Me.y2 = y2
        Me.y1 = y1
        Me.id = id
    End Sub
End Class

具体到反序列化的代码，就很简单了。代码如下：

Dim cardXML As FileStream = New FileStream(xmlPath,FileMode.Open)
'card是类名，也是根节点
Dim serialize As XmlSerializer = New XmlSerializer(GetType(card))
Dim wholeCard As card = serialize.Deserialize(cardXML)
cardXML.Close()

但有的时候，xml是以字符串的形式给出的。这时候我们该如何处理呢？

从反序列化的定义可知，反序列化是把流转为对象。

上面的代码是以文件流的形式来反序列化。如果是字符串的话，我们就需要把字符串存入内存流中，再把内存流反序列化。

Dim descBytes() As Byte = System.Text.Encoding.Unicode.GetBytes(xmlString)
Dim serialize As XmlSerializer = New XmlSerializer(GetType(card))
Dim wholeCard As card = serialize.Deserialize(New MemoryStream(descBytes))

参考文献：Visual.Basic.2010 & NET 4 高级编程