如何将XML字符串转为C#对象并仅读取指定节点（报错求助）

错误原因 #

你的XML根节点是<root>，但当前XmlSerializer初始化时传入的是LocationSettings类型，该类标记了[XmlRoot("locationsettings")]，序列化器期望根节点为<locationsettings>，同时XML中存在<main>等未定义的节点，导致反序列化时触发错误。此外，LocationSettings类中RowSettings的特性使用有误：XML里<locationsettings>直接包含多个<row>节点，而[XmlArrayItem("row")]需要配合外层数组节点（如<rows>）使用，当前特性无法正确匹配XML结构。

解决方案 #

方案一：提取目标节点后反序列化 #

先加载整个XML，定位到<locationsettings>节点，再对该节点的XML内容进行反序列化：

var xmlSettings = $"<?xml version=\"1.0\"?>{item.Settings}";
var doc = new XmlDocument();
doc.LoadXml(xmlSettings);

// 提取locationsettings节点
var locationNode = doc.SelectSingleNode("//locationsettings");
if (locationNode != null)
{
    var locationXml = locationNode.OuterXml;
    using var stringReader = new StringReader(locationXml);
    var serializer = new XmlSerializer(typeof(LocationSettings));
    var tt = serializer.Deserialize(stringReader) as LocationSettings;
}

同时修正LocationSettings类的特性，将[XmlArrayItem("row")]改为[XmlElement("row")]：

[Serializable]
public class LocationSettings
{
    public LocationSettings()
    {
        this.RowSettings = new List<RowSettings>();
    }

    // 直接匹配locationsettings下的row节点
    [XmlElement("row")]
    public List<RowSettings> RowSettings { get; set; }
}

[Serializable]
public class RowSettings
{
    [XmlElement("dealerid")]
    public int dealerid { get; set; }
    [XmlElement("locationid")]
    public int locationid { get; set; }
    [XmlElement("ikquserid")]
    public string? ikquserid { get; set; }
    [XmlElement("ikqpass")]
    public string? ikqpass { get; set; }
}

方案二：定义根节点类匹配完整XML结构 #

创建一个匹配<root>节点的类，仅定义需要的LocationSettings属性，序列化器会自动忽略未定义的<main>节点：

// 根节点类
[Serializable, XmlRoot("root")]
public class RootXml
{
    [XmlElement("locationsettings")]
    public LocationSettings LocationSettings { get; set; }
}

// 修正后的LocationSettings类
[Serializable]
public class LocationSettings
{
    public LocationSettings()
    {
        this.RowSettings = new List<RowSettings>();
    }

    [XmlElement("row")]
    public List<RowSettings> RowSettings { get; set; }
}

// RowSettings类保持不变
[Serializable]
public class RowSettings
{
    [XmlElement("dealerid")]
    public int dealerid { get; set; }
    [XmlElement("locationid")]
    public int locationid { get; set; }
    [XmlElement("ikquserid")]
    public string? ikquserid { get; set; }
    [XmlElement("ikqpass")]
    public string? ikqpass { get; set; }
}

然后直接反序列化整个XML：

var xmlSettings = $"<?xml version=\"1.0\"?>{item.Settings}";
using var stringReader = new StringReader(xmlSettings);
var serializer = new XmlSerializer(typeof(RootXml));
var root = serializer.Deserialize(stringReader) as RootXml;
var tt = root?.LocationSettings;

内容的提问来源于stack exchange，提问作者Muhammad Kamran