将 XML 反序列化为对象返回空值

Question

我正在尝试反序列化 XML 文档，但我使用的代码每次都返回 Null 值。

我有一个这样的 XML

<?xml version="1.0" encoding="utf-8"?>
<RegistrationOpenData xmlns:i="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://example.gov">
<Description>Registration data is collected by ABC XYZ</Description>
<InformationURL>http://www.example.com/html/hpd/property-reg-unit.shtml</InformationURL>
<SourceAgency>ABC Department of Housing</SourceAgency>
<SourceSystem>PREMISYS</SourceSystem>
<StartDate>2016-02-29T00:03:06.642772-05:00</StartDate>
<EndDate i:nil="true" />
<Registrations>
<Registration xmlns:i="http://www.w3.org/2001/XMLSchema-instance">
<RegistrationID>108260</RegistrationID>
<BuildingID>4731</BuildingID>
</Registration>
</Registrations>
</RegistrationOpenData>

为了反序列化，我创建了一个类

using System.Xml.Serialization;
using System.Xml;
[System.CodeDom.Compiler.GeneratedCodeAttribute("xsd", "4.0.30319.1")]
[System.SerializableAttribute()]
[System.Diagnostics.DebuggerStepThroughAttribute()]
[System.ComponentModel.DesignerCategoryAttribute("code")]
[System.Xml.Serialization.XmlTypeAttribute(Namespace="http://example.gov")]
[System.Xml.Serialization.XmlRootAttribute(Namespace="http://example.gov", IsNullable=true)]
public partial class Registration : InfoClass {

  private long registrationIDField;
  private bool registrationIDFieldSpecified;
  private System.Nullable<long> buildingIDField;
  private bool buildingIDFieldSpecified;

  public long RegistrationID
 {
    get
    {
        return this.registrationIDField;
    }
    set
    {
        this.registrationIDField = value;
    }
}
[System.Xml.Serialization.XmlIgnoreAttribute()]
public bool RegistrationIDSpecified {
    get {
        return this.registrationIDFieldSpecified;
    }
    set {
        this.registrationIDFieldSpecified = value;
    }
}

[System.Xml.Serialization.XmlElementAttribute(IsNullable=true)]
public System.Nullable<long> BuildingID {
    get {
        return this.buildingIDField;
    }
    set {
        this.buildingIDField = value;
    }
}

[System.Xml.Serialization.XmlIgnoreAttribute()]
public bool BuildingIDSpecified {
    get {
        return this.buildingIDFieldSpecified;
    }
    set {
        this.buildingIDFieldSpecified = value;
    }
}

我使用的代码是

public void Test()
    {

        Registration RegistrationVal = null;
        var xRoot = new XmlRootAttribute();
        xRoot.ElementName = "RegistrationOpenData";
        xRoot.Namespace = "http://services.hpd.gov";
        xRoot.IsNullable = true;
        var serializer = new XmlSerializer(typeof(Registration), xRoot);
        using (TextReader reader = new StreamReader(@"D:\sample.xml"))
            {
                RegistrationVal = (Registration)serializer.Deserialize(reader);
            }
}

这里总是返回 Null 值。 提前感谢您的帮助。

Answer 1

您的问题出在 xml 中，因为它有一个注册列表。如果您删除 <Registration> 和 <Registrations> 标签，那么它可以工作。您是否需要Registration 和Registrations，因为在这种情况下您必须使用Lists。

你可以像这个例子中那样做 (Deserializing nested xml into C# objects)

并创建一个自己的类Registrations，其中包含List 的Registration 元素。

使用此代码可以正常工作。创建一个超类：

[XmlRoot("RegistrationOpenData")]
public class RegistrationOpenData
{
    [XmlElement("Registrations")]
    public Registrations Regs { get; set; }
}

还有Registrations：

[XmlRoot("Registrations")]
public class Registrations
{
    [XmlElement("Registration")]
    public List<Registration> Regs { get; set; }
}

并且Registration 应该和以前一样。 主函数应该改成这样：

static void Main(string[] args)
{
        RegistrationOpenData RegistrationVal = null;
        var xRoot = new XmlRootAttribute();
        xRoot.ElementName = "RegistrationOpenData";
        xRoot.Namespace = "http://services.hpd.gov";
        xRoot.IsNullable = true;
        var serializer = new XmlSerializer(typeof(RegistrationOpenData), xRoot);
        using (TextReader reader = new StreamReader(@"D:\sample.xml"))
        {
            RegistrationVal = (RegistrationOpenData)serializer.Deserialize(reader);
        }
}