XSD是指XML结构定义 ( XML Schemas Definition )
XML Schema 是DTD的替代品。XML Schema语言也就是XSD。
XML Schema描述了XML文档的结构。可以用一个指定的XML Schema来验证某个XML文档，以检查该XML文档是否符合其要求。文档设计者可以通过XML Schema指定一个XML文档所允许的结构和内容，并可据此检查一个XML文档是否是有效的。XML Schema本身是一个XML文档，它符合XML语法结构。可以用通用的XML解析器解析它。
一个XML Schema会定义：文档中出现的元素、文档中出现的属性、子元素、子元素的数量、子元素的顺序、元素是否为空、元素和属性的数据类型、元素或属性的默认和固定值。
XSD是DTD替代者的原因，一是据将来的条件可扩展，二是比DTD丰富和有用，三是用XML书写，四是支持数据类型，五是支持命名空间。
XSD文件的后缀名为.xsd。
XML Schema的优点:
1) XML Schema基于XML,没有专门的语法
2) XML可以象其他XML文件一样解析和处理
3) XML Schema支持一系列的数据类型(int、float、Boolean、date等)
4) XML Schema提供可扩充的数据模型。
5) XML Schema支持综合命名空间
6) XML Schema支持属性组。
对xml文件的操作：http://www.cnblogs.com/jhtchina/archive/2007/06/05/691610.html
<!-- booksSchema.xml -->
<?xml version='1.0'?>
<!-- This file represents a fragment of a book store inventory database -->
<bookstore xmlns = "schema.xsd">
<book genre="autobiography" publicationdate="1981" ISBN="1-861003-11-0">
<title>The Autobiography of Benjamin Franklin</title>
<author>
<first-name>Benjamin</first-name>
<last-name>Franklin</last-name>
</author>
<price>8.99</price>
</book>
<book genre="novel" publicationdate="1967" ISBN="0-201-63361-2">
<title>The Confidence Man</title>
<author>
<first-name>Herman</first-name>
<last-name>Melville</last-name>
</author>
<price>11.99</price>
</book>
<book genre="philosophy" publicationdate="1991" ISBN="1-861001-57-6">
<title>The Gorgias</title>
<author>
<first-name>Sidas</first-name>
<last-name>Plato</last-name>
</author>
<price>9.99</price>
</book>
</bookstore> <!--
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-->
<!-- schema.xsd -->
<xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema"
xmlns="schema.xsd"
elementFormDefault="qualified"
targetNamespace="schema.xsd">
<xsd:element name="bookstore" type="bookstoreType"/>
<xsd:complexType name="bookstoreType">
<xsd:sequence maxOccurs="unbounded">
<xsd:element name="book" type="bookType"/>
</xsd:sequence>
</xsd:complexType>
<xsd:complexType name="bookType">
<xsd:sequence>
<xsd:element name="title" type="xsd:string"/>
<xsd:element name="author" type="authorName"/>
<xsd:element name="price" type="xsd:decimal"/>
</xsd:sequence>
<xsd:attribute name="genre" type="xsd:string"/>
<xsd:attribute name="publicationdate" type="xsd:string"/>
<xsd:attribute name="ISBN" type="xsd:string"/>
</xsd:complexType>
<xsd:complexType name="authorName">
<xsd:sequence>
<xsd:element name="first-name" type="xsd:string"/>
<xsd:element name="last-name" type="xsd:string"/>
</xsd:sequence>
</xsd:complexType>
</xsd:schema> <!--
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-->
<!-- bookSchemaFail.xml -->
<?xml version='1.0'?>
<bookstore xmlns="schema.xsd">
<book>
<author>
<first-name>Benjamin</first-name>
<last-name>Franklin</last-name>
</author>
</book>
<book genre="novel">
<title>The Confidence Man</title>
<author>
<first-name>Herman</first-name>
<last-name>Melville</last-name>
</author>
<price>11.99</price>
</book>
<book genre="philosophy">
<title>The Gorgias</title>
<author>
<name>Plato</name>
</author>
<price>9.99</price>
</book>
</bookstore> <!--
Code highlighting produced by Actipro CodeHighlighter (freeware)
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--> using System;
using System.Xml;
using System.Xml.Schema;
using System.IO;
namespace SchemaData
{
/// <summary>
/// Validator 的摘要说明。
/// </summary>
public class Validator
{
private const String document3 = "booksSchema.xml";
private const String document4 = "booksSchemaFail.xml";
private const String document5 = "schema.xsd";
private XmlValidatingReader myXmlValidatingReader = null;
private XmlTextReader myXmlTextReader = null;
private Boolean Success = true;
private String[] args = {document3, document4, document5};
public Validator()
{
//
// TODO: 在此处添加构造函数逻辑
//
}
public void Run()
{
try
{
XmlSchemaCollection myXmlSchemaCollection = new XmlSchemaCollection();
myXmlSchemaCollection.Add("schema.xsd" , new XmlTextReader(args[2]));
// 用架构验证 XML 文件
Success = true;
Console.WriteLine();
Console.WriteLine("正在用架构文件 schema.xsd 验证 XML 文件 booksSchema.xml ...");
myXmlTextReader = new XmlTextReader (args[0]);
myXmlValidatingReader = new XmlValidatingReader(myXmlTextReader);
myXmlValidatingReader.Schemas.Add(myXmlSchemaCollection);
myXmlValidatingReader.ValidationType = ValidationType.Schema;
Validate();
// 架构验证失败
Success = true;
Console.WriteLine();
Console.WriteLine("正在用架构文件 schema.xsd 验证 XML 文件 booksSchemaFail.xml ...");
myXmlTextReader = new XmlTextReader (args[1]);
myXmlValidatingReader = new XmlValidatingReader(myXmlTextReader);
myXmlValidatingReader.Schemas.Add(myXmlSchemaCollection);
myXmlValidatingReader.ValidationType = ValidationType.Schema;
Validate();
}
catch (Exception e)
{
Console.WriteLine("异常：" + e.ToString());
}
finally
{
// 通过 XmlTextReader 完成
if (myXmlValidatingReader != null)
myXmlValidatingReader.Close();
}
}
private void Validate()
{
try
{
// 设置验证事件处理程序
myXmlValidatingReader.ValidationEventHandler += new ValidationEventHandler (this.ValidationEventHandle);
// 读取 XML 数据
while (myXmlValidatingReader.Read()){}
Console.WriteLine ("验证已完成。验证 {0}", (Success==true ? "成功" : "失败"));
}
catch (XmlException e)
{
Console.WriteLine ("Xml 异常：" + e.ToString());
}
catch (Exception e)
{
Console.WriteLine ("异常：" + e.ToString());
}
}
public void ValidationEventHandle (object sender, ValidationEventArgs args)
{
Success = false;
Console.WriteLine("\t验证错误：" + args.Message);
if (args.Severity == XmlSeverityType.Warning)
{
Console.WriteLine("未找到要强制验证的架构。");
}
else
if (args.Severity == XmlSeverityType.Error)
{
Console.WriteLine("验证实例文档时发生验证错误。");
}
if (args.Exception != null) // XSD 架构验证错误
{
Console.WriteLine(args.Exception.SourceUri + "," + args.Exception.LinePosition + "," + args.Exception.LineNumber);
}
//if (myXmlValidatingReader.Reader.LineNumber > 0)
//{
// Console.WriteLine("Line: "+ myXmlValidatingReader.Reader.LineNumber + " Position: " + myXmlValidatingReader.Reader.LinePosition);
//}
}
}
}
