为什么在使用 DataContractJsonSerializer 序列化后数组显示为 null?

Why are arrays being shown as null after serializing using DataContractJsonSerializer?

有很多关于使用 DataContractJsonSerializer 序列化和反序列化数组的问题(包括我提出的一个问题:),但 none 似乎回答了我当前遇到的问题。

我正在将 XML 字符串转换为 JSON 字符串,方法是使用 DataContractJsonSerializer 将 XML 反序列化为 DataContract 对象,然后将该对象序列化为 JSON。我的方法与我在许多其他对象上使用的方法相同,所有这些对象都完美地序列化为 JSON,但我有一个对象,其中数组 属性 在序列化后始终呈现为 null .

类定义如下:-

[DataContract]
public class Order
{
    [DataMember(Name = "consignments")]
    [XmlElement("consignments")]
    public Consignment[] Consignments { get; set; }
}

[DataContract]
public class Consignment
{
    [DataMember(Name = "conh_id")]
    [XmlElement("conh_id")]
    public string ConsignmentHeaderId { get; set; }

    [DataMember(Name = "conh_status")]
    [XmlElement("conh_status")]
    public string ConsignmentHeaderStatus { get; set; }

    [DataMember(Name = "consignmententries")]
    [XmlElement("consignmententries")]
    public ConsignmentEntry[] ConsignmentEntries { get; set; }
}

我正在使用的 XML 看起来像这样:-

<order>
  <consignments>
    <consignment>
      <conh_id>A19708176</conh_id>
      <conh_status>ACCEPTED</conh_status>
      <consignmententries>
        <consignmententry>
          <conl_lineNbr>10000</conl_lineNbr>
          <conl_sku>SEC01XXZBUXXX</conl_sku>
          <conl_original_qty>1</conl_original_qty>
        </consignmententry>
      </consignmententries>
    </consignment>
  </consignments>
</order>

反序列化和序列化在以下方法中完成:-

private object DeserialiseXml(string xml)
{
    var serialiser = new XmlSerializer(typeof(Order));
    var stringReader = new StringReader(xml);
    var result = serialiser.Deserialize(stringReader);

    return result;
}

private string SerialiseJson(object serialisable)
{
    using (MemoryStream stream = new MemoryStream())
    {
        var serialiser = new DataContractJsonSerializer(serialisable.GetType());
        serialiser.WriteObject(stream, serialisable);
        var json = Encoding.UTF8.GetString(stream.ToArray());

        return json;
    } 
}

当我测试它时,结果 JSON 中的 Consignments 属性 始终为 null。

"order": {
  "consignments": [
    {
      "conh_id": null,
      "conh_status": null,
      "consignmententries": null
    }
  ]
}

调试显示在反序列化步骤后创建的对象中此 属性 为空,因此问题出在 XML 反序列化而不是 JSON 序列化。

我需要对我的对象模型进行哪些更改才能正确转换数组?

当您从 XML 反序列化而不是序列化到 JSON 时,您的问题就会发生。在您的 XML 中,集合已序列化为两个级别:外部容器元素和每个项目的元素:

  <consignments>
    <consignment>
       <!-- Consignment data -->
    </consignment>
  </consignments>

  <consignmententries>
    <consignmententry>
       <!-- Entry data -->
    </consignmententry>
  </consignmententries>

(为了比较,在 the Labels XML collection has a single level). Thus you need to use [XmlArray(string name)] and [XmlArrayItem(string itemName)]中指定外层和内层元素名称:

[DataContract]
[XmlRoot("order")]
public class Order
{
    [DataMember(Name = "consignments")]
    [XmlArray("consignments")]
    [XmlArrayItem("consignment")]
    public Consignment[] Consignments { get; set; }
}

[DataContract]
public class Consignment
{
    [DataMember(Name = "conh_id")]
    [XmlElement("conh_id")]
    public string ConsignmentHeaderId { get; set; }

    [DataMember(Name = "conh_status")]
    [XmlElement("conh_status")]
    public string ConsignmentHeaderStatus { get; set; }

    [DataMember(Name = "consignmententries")]
    [XmlArray("consignmententries")]
    [XmlArrayItem("consignmententry")]
    public ConsignmentEntry[] ConsignmentEntries { get; set; }
}

相反,将属性 [XmlElement] 添加到集合会告诉 XmlSerializer 集合应该在没有外部容器元素的情况下进行序列化。

您还需要在 Order 中添加 [XmlRoot("order")] 以指定根元素名称。

现在您的 XML 将成功反序列化。