使用序列化将 XML 数据转换为对象，反之亦然

引言

将 XML 保存到类对象可以提供更大的灵活性和可维护性。此外，与使用 DataSet 相比，这是从 Web 服务返回数据的首选方式。将 XML 保存到类对象称为序列化，而使用反向过程读取则称为反序列化。

流程/示例

让我们以一个名为 Emp.XSD 的 XSD 为例

<?xml version="1.0" encoding="UTF-8"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" 
     elementFormDefault="qualified" attributeFormDefault="unqualified">
 <xs:element name="Emp">
  <xs:complexType>
   <xs:sequence>
    <xs:element name="EmpInfo" type="EmpInfo"/>
   </xs:sequence>
  </xs:complexType>
 </xs:element>
 <xs:complexType name="EmpInfo">
  <xs:sequence>
   <xs:element name="Code" type="requiredString"/>
   <xs:element name="FirstName" type="requiredString"/>
   <xs:element name="LastName" type="requiredString"/>
   <xs:element name="Destination" type="requiredString"/>
  </xs:sequence>
 </xs:complexType>
 <xs:simpleType name="requiredString">
  <xs:annotation>
   <xs:documentation>template for required strings</xs:documentation>
  </xs:annotation>
  <xs:restriction base="xs:string">
   <xs:minLength value="1"/>
  </xs:restriction>
 </xs:simpleType>
 <xs:simpleType name="optionalString">
  <xs:annotation>
   <xs:documentation>template for optional strings</xs:documentation>
  </xs:annotation>
  <xs:restriction base="xs:string">
   <xs:minLength value="0"/>
  </xs:restriction>
 </xs:simpleType>
</xs:schema>

现在，要从 XSD 转换类，我们将运行以下命令

xsd C:\Emp.xsd /t:lib /l:cs /c

从 Visual Studio .NET 2003 命令提示符。这将创建一个名为 Emp 的类文件。

EMP 类

//------------------------------------------------------------------------------
// <autogenerated>
//     This code was generated by a tool.
//     Runtime Version: 1.1.4322.2032

//
//     Changes to this file may cause incorrect behavior and will be lost if 
//     the code is regenerated.
// </autogenerated>
//------------------------------------------------------------------------------

// 
// This source code was auto-generated by xsd, Version=1.1.4322.2032.
// 
using System.Xml.Serialization;

/// <remarks/>
[System.Xml.Serialization.XmlRootAttribute(Namespace="", IsNullable=false)]
public class Emp {
    
    /// <remarks/>
    public EmpInfo EmpInfo;
}

/// <remarks/>
public class EmpInfo {
    
    /// <remarks/>
    public string Code;
    
    /// <remarks/>
    public string FirstName;
    
    /// <remarks/>
    public string LastName;
    
    /// <remarks/>
    public string Destination;
}

现在，我们可以使用以下函数将员工 XML 数据保存到该类

  /// <summary>
  /// Returns an emp xsd class object based on the xml data passed
  /// </summary>
  /// <param name="xml">xml data of employee</param>
  /// <returns></returns>
  public Emp EmpObject(string xml)
  {
   StringReader stream = null;
   XmlTextReader reader = null;
   try
   {
    // serialise to object
    XmlSerializer serializer = new XmlSerializer(typeof(Emp));
    stream = new StringReader(xml); // read xml data
    reader = new XmlTextReader(stream);  // create reader
    // covert reader to object
    return (Emp)serializer.Deserialize(reader);
   }
   catch
   {
    return null;
   }
   finally
   {
    if(stream != null) stream.Close();
    if(reader != null) reader.Close();
   }
  }

要根据 Emp 类对象获取 XML，请使用以下函数

  /// <summary>
  /// Returns the xml as string based on emp object values
  /// </summary>
  /// <param name="emp">object that would be converted into xml</param>
  /// <returns></returns>
  public string EmpXml(Emp emp)
  {
   MemoryStream stream = null;
   TextWriter writer = null;
   try
   {
    stream = new MemoryStream(); // read xml in memory
    writer = new StreamWriter(stream, Encoding.Unicode) ;
    // get serialise object
    XmlSerializer serializer = new XmlSerializer(typeof(Emp));
    serializer.Serialize(writer, emp); // read object
    int count = (int) stream.Length; // saves object in memory stream
    byte[] arr = new byte[count];
    stream.Seek(0, SeekOrigin.Begin);
    // copy stream contents in byte array
    stream.Read(arr, 0, count);
    UnicodeEncoding utf = new UnicodeEncoding(); // convert byte array to string
    return utf.GetString(arr).Trim();
   }
   catch
   {
    return string.Empty;
   }
   finally
   {
    if(stream != null) stream.Close();
    if(writer != null) writer.Close();
   }
  }