如何反序列化带不同type属性的XML数组并解决i:type属性报错问题

问题根源 #

报错由两个核心配置错误导致：

1. 数组节点名称配置错误：XML中的节点名_x003C_CustomizationsForTypeList_x003E_k__BackingField是<CustomizationsForTypeList>k__BackingField的XML编码形式，XmlArrayAttribute需要填写编码后的实际节点名，而不是原始的自动属性 backing field 名称。
2. 派生类XmlType命名空间配置错误：i:type属性的取值对应的类型名称，所属命名空间是根节点的Dynamics AX业务命名空间，不是http://www.w3.org/2001/XMLSchema-instance（这个只是xsi:type属性本身的命名空间，和类型所属命名空间无关）。

修正后的类定义 #

[XmlRoot(Namespace = "http://schemas.datacontract.org/2004/07/Microsoft.Dynamics.AX.Security.Management")]
public class SecurityCustomizationData
{
    // 填写XML中实际存在的编码后的节点名
    [XmlArray("_x003C_CustomizationsForTypeList_x003E_k__BackingField")]
    [XmlArrayItem("BaseRepositoryCustomizations", Type = typeof(RoleRepoCust))]
    [XmlArrayItem("BaseRepositoryCustomizations", Type = typeof(DutyRepoCust))]
    [XmlArrayItem("BaseRepositoryCustomizations", Type = typeof(PrivilegeRepoCust))]
    public BaseRepositoryCustomizations[] CustomizationsForTypeList { get; set; }
}

public class BaseRepositoryCustomizations
{
}

// 命名空间替换为根节点的业务命名空间
[XmlType(TypeName = "RepositoryCustomizationsOfAxSecurityRoleNcCATIYq", Namespace = "http://schemas.datacontract.org/2004/07/Microsoft.Dynamics.AX.Security.Management")]
public class RoleRepoCust : BaseRepositoryCustomizations
{
}

[XmlType(TypeName = "RepositoryCustomizationsOfAxSecurityDutyNcCATIYq", Namespace = "http://schemas.datacontract.org/2004/07/Microsoft.Dynamics.AX.Security.Management")]
public class DutyRepoCust : BaseRepositoryCustomizations
{
}

[XmlType(TypeName = "RepositoryCustomizationsOfAxSecurityPrivilegeNcCATIYq", Namespace = "http://schemas.datacontract.org/2004/07/Microsoft.Dynamics.AX.Security.Management")]
public class PrivilegeRepoCust : BaseRepositoryCustomizations
{
}

验证反序列化&序列化代码 #

// 反序列化
var serializer = new XmlSerializer(typeof(SecurityCustomizationData));
using var reader = new StringReader("你的XML内容字符串");
var result = (SecurityCustomizationData)serializer.Deserialize(reader);

// 序列化回XML可自动生成正确的i:type属性
using var writer = new StringWriter();
serializer.Serialize(writer, result);
var xmlOutput = writer.ToString();

补充说明 #

如果不需要保留原始的backing field节点名，后续序列化时输出更整洁的XML，可以给XmlArrayAttribute配置ElementName为自定义的名称比如CustomizationsForTypeList，只要和你实际需要的输出格式匹配即可。

内容的提问来源于stack exchange，提问作者Kempeth