如何从大型XML的指定片段反序列化生成Item对象列表

需要从大型XML中仅提取<items>节点下的所有<item>数据，生成Item对象列表。

示例XML结构 #

<tXML>
    <nameOfUser>MK</nameOfUser>
    <amouthOfPO>14</amouthOfPO>
    <todayDate></todayDate>
    <warehouses>
        <warehouse id="1">
            <name>AD1</name>
        </warehouse>
        <warehouse id="2">
            <name>AD2</name>
        </warehouse>
        <warehouse id="3">
            <name>AD3</name>
        </warehouse>
    </warehouses>
    <items>
        <warehause id="1">
            <items>
                <item>
                    <name>item1</name>
                    <protectionLevel>AMB</protectionLevel>
                    <description>DescAMB1FORID1</description>
                </item>
                <item>
                    <name>item2</name>
                    <protectionLevel>CHL</protectionLevel>
                    <description>DescCHL1FORID1</description>
                </item>
                <item>
                    <name>item3</name>
                    <protectionLevel>AMB</protectionLevel>
                    <description>3</description>
                </item>
            </items>
        </warehause>
        <warehause id="3">
            <items>
                <item>
                    <name>item1AMB2222</name>
                    <protectionLevel>AMBB222222</protectionLevel>
                    <description>DESCRIPTIONITEM1AM222222B</description>
                </item>
                <item>
                    <name>item222222CHL</name>
                    <protectionLevel>C222222222LL</protectionLevel>
                    <description>ITEM2CH22ILLERAD1</description>
                </item>
                <item>
                    <name>2222222222223</name>
                    <protectionLevel>222222223</protectionLevel>
                    <description>3222222222222</description>
                </item>
            </items>
        </warehause>
        <warehause id="3">
            <items>
                <item>
                    <name>item1333333AMB</name>
                    <protectionLevel>AM3333BB</protectionLevel>
                    <description>DESCR333IPTIONITEM1AMB</description>
                </item>
                <item>
                    <name>item233333CHL</name>
                    <protectionLevel>C33333HLL</protectionLevel>
                    <description>ITEM2CHI333LLERAD1</description>
                </item>
                <item>
                    <name>33</name>
                    <protectionLevel>33</protectionLevel>
                    <description>33</description>
                </item>
            </items>
        </warehause>
    </items>
</tXML>

已定义Item类 #

namespace UseFiles
{
    public class Item
    {
        public string Name { get; set; }
        public string ProtectionLevel { get; set; }
        public string Description { get; set; }
    }
}

优先推荐 XmlReader + XmlSerializer 混合方案，优势如下：

• 流式读取不需要加载整个XML到内存，适配GB级超大XML，内存占用极低
• 无需手动逐个给属性赋值，后续字段增减只需修改Item类注解，维护成本低
• 直接定位目标节点反序列化，忽略无关节点，处理效率更高

步骤1：给Item类添加序列化注解 #

using System.Xml.Serialization;

namespace UseFiles
{
    [XmlRoot("item")]
    public class Item
    {
        [XmlElement("name")]
        public string Name { get; set; }

        [XmlElement("protectionLevel")]
        public string ProtectionLevel { get; set; }

        [XmlElement("description")]
        public string Description { get; set; }
    }
}

步骤2：解析逻辑实现 #

using System.Collections.Generic;
using System.Xml;
using System.Xml.Serialization;

public List<Item> ParseItemsFromXml(string xmlFilePath)
{
    var items = new List<Item>();
    var serializer = new XmlSerializer(typeof(Item));
    
    // 流式读取XML，不加载全量内容到内存
    using (var reader = XmlReader.Create(xmlFilePath))
    {
        // 定位到所有<item>节点
        while (reader.ReadToFollowing("item"))
        {
            // 直接反序列化当前<item>节点为对象
            var item = (Item)serializer.Deserialize(reader.ReadSubtree());
            items.Add(item);
        }
    }
    return items;
}

如果不想修改Item类加注解，且XML体积不大的场景可以用，代码更灵活但维护成本更高：

using System.Collections.Generic;
using System.Xml;

public List<Item> ParseItemsFromXmlManual(string xmlFilePath)
{
    var items = new List<Item>();
    var xmlDoc = new XmlDocument();
    xmlDoc.Load(xmlFilePath);
    
    // XPath查询所有目标<item>节点
    XmlNodeList itemNodes = xmlDoc.SelectNodes("//tXML/items//item");
    
    foreach (XmlNode itemNode in itemNodes)
    {
        var item = new Item
        {
            Name = itemNode.SelectSingleNode("name")?.InnerText,
            ProtectionLevel = itemNode.SelectSingleNode("protectionLevel")?.InnerText,
            Description = itemNode.SelectSingleNode("description")?.InnerText
        };
        items.Add(item);
    }
    return items;
}

内容的提问来源于stack exchange，提问作者Mateusz Kaleta