Question

我试图反序列化XML，其中一些相同的名称标签具有不同的xsi类型：

<user-defined-data-row>
  <field name="entity">
    <field-value xsi:type="field-text-valueType">
      <value>Test</value>
    </field-value>
  </field>
  <field name="expiry_date">
    <field-value xsi:type="field-date-valueType">
      <value>2001-10-07</value>
    </field-value>
  </field>
</user-defined-data-row>

通过将xml反序列化为此模型很容易实现：

[XmlRoot(ElementName = "field-value", Namespace = "http://www.crsoftwareinc.com/xml/ns/titanium/common/v1_0")]
[XmlType("field-text-valueType")]
public class Fieldvalue
{
    [XmlElement(ElementName = "value", Namespace = "http://www.crsoftwareinc.com/xml/ns/titanium/common/v1_0")]
    public string Value { get; set; }
}

唯一不同的是XML中的类型：

字段-文本VALUETYPE

字段-日期VALUETYPE

如何使C＃类使用类似

的内容来解释这两种类型

[XmlType("field-text-valueType")]

编辑：反序列化不序列化

Answer 1

您在XML中看到的xsi:type属性是标准的W3C XML Schema属性，允许元素明确指定其类型;有关详细信息，请参阅here。正如Xsi:type Attribute Binding Support中所述，XmlSerializer支持这种多态类型反序列化机制，特别是使用XmlIncludeAttribute。

首先，按如下方式定义抽象基类FieldValue：

public static class XmlNamespaces
{
    public const string Crsoftwareinc = "http://www.crsoftwareinc.com/xml/ns/titanium/common/v1_0";
}

[XmlRoot("field-value", Namespace = XmlNamespaces.Crsoftwareinc)]
[XmlType("field-value", Namespace = XmlNamespaces.Crsoftwareinc)]
[XmlInclude(typeof(TextFieldValue)), 
XmlInclude(typeof(DateFieldValue))]
public abstract partial class FieldValue
{
    // It's not necessary to have this in the base class but I usually find it convenient.
    public abstract object GetValue();
}

接下来，针对每个可能的xsi:type="XXX"值，定义FieldValue与xsi:type值匹配的派生类型[XmlInclude(typeof(TDerivedFieldValue))]。用每个[XmlRoot("field-text-valueType", Namespace = XmlNamespaces.Crsoftwareinc)] [XmlType("field-text-valueType", Namespace = XmlNamespaces.Crsoftwareinc)] public class TextFieldValue : FieldValue { [XmlElement("value")] public string Value { get; set; } public override object GetValue() { return Value; } } [XmlRoot("field-date-valueType", Namespace = XmlNamespaces.Crsoftwareinc)] [XmlType("field-date-valueType", Namespace = XmlNamespaces.Crsoftwareinc)] public class DateFieldValue : FieldValue { [XmlElement("value", DataType = "date")] public DateTime Value { get; set; } public override object GetValue() { return Value; } }属性装饰基类（如上所示）：

<field>

然后定义与[XmlRoot("field", Namespace = XmlNamespaces.Crsoftwareinc)] [XmlType("field", Namespace = XmlNamespaces.Crsoftwareinc)] public class Field { [XmlAttribute("name")] public string Name { get; set; } [XmlElement("field-value")] public FieldValue FieldValue { get; set; } } [XmlRoot("user-defined-data-row", Namespace = XmlNamespaces.Crsoftwareinc)] [XmlType("user-defined-data-row", Namespace = XmlNamespaces.Crsoftwareinc)] public class UserDefinedDataRow { [XmlElement("field")] public List<Field> Fields { get; set; } } // The XML for the root object is not shown so this is just a stub [XmlRoot("root", Namespace = XmlNamespaces.Crsoftwareinc)] [XmlType("root", Namespace = XmlNamespaces.Crsoftwareinc)] public class RootObject { [XmlElement("user-defined-data-row")] public List<UserDefinedDataRow> Rows { get; set; } }和其他更高元素对应的包含类型，如下所示：

FieldValue

注意：

如果基类XmlSerializer在via XmlTypeAttribute.TypeName中指定了命名空间，那么派生类也必须，否则[XmlType]会抛出错误。

定义[XmlElement(Namespace = "http://www.crsoftwareinc.com/xml/ns/titanium/common/v1_0")]命名空间后，它会自动应用于所有序列化属性，因此无需通过"http://www.crsoftwareinc.com/xml/ns/titanium/common/v1_0"属性指定相同的命名空间。
我厌倦了反复键入命名空间FieldType，因此我将其提取为常量。
可以轻松添加[XmlRoot("field-decimal-valueType", Namespace = XmlNamespaces.Crsoftwareinc)] [XmlType("field-decimal-valueType", Namespace = XmlNamespaces.Crsoftwareinc)] public class DecimalFieldValue : FieldValue { [XmlElement("value")] public decimal Value { get; set; } public override object GetValue() { return Value; } } [XmlInclude(typeof(DecimalFieldValue))] public abstract partial class FieldValue { }的其他派生类型，例如：
```
[XmlInclude(typeof(DecimalFieldValue))]
```
这样做时不要忘记添加<field-value>。
如果您已为您尝试反序列化的XML提供了XSD，则会指定xsd.exe的可能类型，例如：如XmlTypeAttribute.Namespace中所示的<xsd:extension>元素，然后Generating XML Documents from XML Schemas: Abstract Types将生成包含适当类型层次结构的类。但是，如果您只拥有XML，那么xsi:type和xsd.exe将不使用任何xsi:属性生成正确的类型层次结构。

有关此限制的详情，请参阅 Paste XML as Classes 。

您的XML格式不正确，因为它省略了xmlns="http://www.crsoftwareinc.com/xml/ns/titanium/common/v1_0"命名空间的声明。此外，未定义默认名称空间<root xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://www.crsoftwareinc.com/xml/ns/titanium/common/v1_0"> <user-defined-data-row>  </user-defined-data-row> </root>，因此没有任何元素实际位于此名称空间中。因此，我假设您的XML是一些有效的较大文档的片段，例如

FAILURE: Build failed with an exception.

* Where:
Build file '/home/travis/build/ir2pid/AndroidPOC2/app/build.gradle' line: 1

* What went wrong:
A problem occurred evaluating project ':app'.
> Failed to apply plugin [id 'com.android.application']
   > Minimum supported Gradle version is 4.1. Current version is 4.0.1. If using the gradle wrapper, try editing the distributionUrl in /home/travis/build/ir2pid/AndroidPOC2/gradle/wrapper/gradle-wrapper.properties to gradle-4.1-all.zip

* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output.

BUILD FAILED in 40s

travis_time:end:06d6b207:start=1527276803217824665,finish=1527276844181358996,duration=40963534331
[0K
[31;1mThe command "gradle wrapper --gradle-version 4.1" failed and exited with 1 during .[0m

Your build has been stopped.

示例工作.Net小提琴xsi:type attribute messing up C# XML deserialization。

使用多种类型

1 个答案: