xsi：type属性搞乱了C＃XML反序列化

时间：2016-04-01 16:46:19

标签： c# xml xsd deserialization opencover

我使用XSD.exe根据XML模式（.xsd文件）自动生成C＃对象。我正在反序列化OpenCover输出，但其中一个部分类没有正确生成。

这是导致异常的行：

<MethodPoint xsi:type="SequencePoint" vc="0" uspid="1" ordinal="0" offset="0" sl="19" sc="9" el="19" ec="10" bec="0" bev="0" fileid="1" />

这是MethodPoint类的缩短版本：

[System.CodeDom.Compiler.GeneratedCodeAttribute("xsd", "4.0.30319.33440")]
[System.SerializableAttribute()]
[System.Diagnostics.DebuggerStepThroughAttribute()]
[System.ComponentModel.DesignerCategoryAttribute("code")]
[System.Xml.Serialization.XmlTypeAttribute(AnonymousType=true)]
public partial class CoverageSessionModulesModuleClassesClassMethodsMethodMethodPoint {
    private string vcField;
    private string uspidField;
    private string ordinalField;
    private string offsetField;
    private string slField;
    private string scField;
    private string elField;
    private string ecField;
    private string becField;
    private string bevField;
    private string fileidField;
}

现在我经历了很多.xml文件，但是OpenCover输出文件是唯一一个在属性中包含冒号的文件。 MethodPoint对象也是唯一在属性中包含冒号的对象。如您所见，该类不包含xsi:type属性，并且我知道只是添加它将因冒号而无效。你如何处理xsi前缀？

以下是从其中一个OpenCover XML文件生成的原始.xsd 

<?xml version="1.0" encoding="utf-8"?>
<xs:schema id="CoverageSession" xmlns="" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:msdata="urn:schemas-microsoft-com:xml-msdata">
  <xs:element name="Summary">
    <xs:complexType>
      <xs:attribute name="numSequencePoints" type="xs:string" />
      <xs:attribute name="visitedSequencePoints" type="xs:string" />
      <xs:attribute name="numBranchPoints" type="xs:string" />
      <xs:attribute name="visitedBranchPoints" type="xs:string" />
      <xs:attribute name="sequenceCoverage" type="xs:string" />
      <xs:attribute name="branchCoverage" type="xs:string" />
      <xs:attribute name="maxCyclomaticComplexity" type="xs:string" />
      <xs:attribute name="minCyclomaticComplexity" type="xs:string" />
      <xs:attribute name="visitedClasses" type="xs:string" />
      <xs:attribute name="numClasses" type="xs:string" />
      <xs:attribute name="visitedMethods" type="xs:string" />
      <xs:attribute name="numMethods" type="xs:string" />
    </xs:complexType>
  </xs:element>
  <xs:element name="CoverageSession" msdata:IsDataSet="true" msdata:UseCurrentLocale="true">
    <xs:complexType>
      <xs:choice minOccurs="0" maxOccurs="unbounded">
        <xs:element ref="Summary" />
        <xs:element name="Modules">
          <xs:complexType>
            <xs:sequence>
              <xs:element name="Module" minOccurs="0" maxOccurs="unbounded">
                <xs:complexType>
                  <xs:sequence>
                    <xs:element name="FullName" type="xs:string" minOccurs="0" msdata:Ordinal="1" />
                    <xs:element name="ModuleName" type="xs:string" minOccurs="0" msdata:Ordinal="2" />
                    <xs:element ref="Summary" minOccurs="0" maxOccurs="unbounded" />
                    <xs:element name="Files" minOccurs="0" maxOccurs="unbounded">
                      <xs:complexType>
                        <xs:sequence>
                          <xs:element name="File" minOccurs="0" maxOccurs="unbounded">
                            <xs:complexType>
                              <xs:attribute name="uid" type="xs:string" />
                              <xs:attribute name="fullPath" type="xs:string" />
                            </xs:complexType>
                          </xs:element>
                        </xs:sequence>
                      </xs:complexType>
                    </xs:element>
                    <xs:element name="Classes" minOccurs="0" maxOccurs="unbounded">
                      <xs:complexType>
                        <xs:sequence>
                          <xs:element name="Class" minOccurs="0" maxOccurs="unbounded">
                            <xs:complexType>
                              <xs:sequence>
                                <xs:element name="FullName" type="xs:string" minOccurs="0" />
                                <xs:element ref="Summary" minOccurs="0" maxOccurs="unbounded" />
                                <xs:element name="Methods" minOccurs="0" maxOccurs="unbounded">
                                  <xs:complexType>
                                    <xs:sequence>
                                      <xs:element name="Method" minOccurs="0" maxOccurs="unbounded">
                                        <xs:complexType>
                                          <xs:sequence>
                                            <xs:element name="MetadataToken" type="xs:string" minOccurs="0" msdata:Ordinal="1" />
                                            <xs:element name="Name" type="xs:string" minOccurs="0" msdata:Ordinal="2" />
                                            <xs:element ref="Summary" minOccurs="0" maxOccurs="unbounded" />
                                            <xs:element name="FileRef" minOccurs="0" maxOccurs="unbounded">
                                              <xs:complexType>
                                                <xs:attribute name="uid" type="xs:string" />
                                              </xs:complexType>
                                            </xs:element>
                                            <xs:element name="SequencePoints" minOccurs="0" maxOccurs="unbounded">
                                              <xs:complexType>
                                                <xs:sequence>
                                                  <xs:element name="SequencePoint" minOccurs="0" maxOccurs="unbounded">
                                                    <xs:complexType>
                                                      <xs:attribute name="vc" type="xs:string" />
                                                      <xs:attribute name="uspid" type="xs:string" />
                                                      <xs:attribute name="ordinal" type="xs:string" />
                                                      <xs:attribute name="offset" type="xs:string" />
                                                      <xs:attribute name="sl" type="xs:string" />
                                                      <xs:attribute name="sc" type="xs:string" />
                                                      <xs:attribute name="el" type="xs:string" />
                                                      <xs:attribute name="ec" type="xs:string" />
                                                      <xs:attribute name="bec" type="xs:string" />
                                                      <xs:attribute name="bev" type="xs:string" />
                                                      <xs:attribute name="fileid" type="xs:string" />
                                                    </xs:complexType>
                                                  </xs:element>
                                                </xs:sequence>
                                              </xs:complexType>
                                            </xs:element>
                                            <xs:element name="BranchPoints" minOccurs="0" maxOccurs="unbounded">
                                              <xs:complexType>
                                                <xs:sequence>
                                                  <xs:element name="BranchPoint" minOccurs="0" maxOccurs="unbounded">
                                                    <xs:complexType>
                                                      <xs:attribute name="vc" type="xs:string" />
                                                      <xs:attribute name="uspid" type="xs:string" />
                                                      <xs:attribute name="ordinal" type="xs:string" />
                                                      <xs:attribute name="offset" type="xs:string" />
                                                      <xs:attribute name="sl" type="xs:string" />
                                                      <xs:attribute name="path" type="xs:string" />
                                                      <xs:attribute name="offsetend" type="xs:string" />
                                                      <xs:attribute name="fileid" type="xs:string" />
                                                      <xs:attribute name="offsetchain" type="xs:string" />
                                                    </xs:complexType>
                                                  </xs:element>
                                                </xs:sequence>
                                              </xs:complexType>
                                            </xs:element>
                                            <xs:element name="MethodPoint" minOccurs="0" maxOccurs="unbounded">
                                              <xs:complexType>
                                                <xs:attribute name="vc" type="xs:string" />
                                                <xs:attribute name="uspid" type="xs:string" />
                                                <xs:attribute name="ordinal" type="xs:string" />
                                                <xs:attribute name="offset" type="xs:string" />
                                                <xs:attribute name="sl" type="xs:string" />
                                                <xs:attribute name="sc" type="xs:string" />
                                                <xs:attribute name="el" type="xs:string" />
                                                <xs:attribute name="ec" type="xs:string" />
                                                <xs:attribute name="bec" type="xs:string" />
                                                <xs:attribute name="bev" type="xs:string" />
                                                <xs:attribute name="fileid" type="xs:string" />
                                              </xs:complexType>
                                            </xs:element>
                                          </xs:sequence>
                                          <xs:attribute name="visited" type="xs:string" />
                                          <xs:attribute name="cyclomaticComplexity" type="xs:string" />
                                          <xs:attribute name="sequenceCoverage" type="xs:string" />
                                          <xs:attribute name="branchCoverage" type="xs:string" />
                                          <xs:attribute name="isConstructor" type="xs:string" />
                                          <xs:attribute name="isStatic" type="xs:string" />
                                          <xs:attribute name="isGetter" type="xs:string" />
                                          <xs:attribute name="isSetter" type="xs:string" />
                                          <xs:attribute name="skippedDueTo" type="xs:string" />
                                        </xs:complexType>
                                      </xs:element>
                                    </xs:sequence>
                                  </xs:complexType>
                                </xs:element>
                              </xs:sequence>
                            </xs:complexType>
                          </xs:element>
                        </xs:sequence>
                      </xs:complexType>
                    </xs:element>
                  </xs:sequence>
                  <xs:attribute name="skippedDueTo" type="xs:string" />
                  <xs:attribute name="hash" type="xs:string" />
                </xs:complexType>
              </xs:element>
            </xs:sequence>
          </xs:complexType>
        </xs:element>
      </xs:choice>
    </xs:complexType>
  </xs:element>
</xs:schema>

1 个答案:

答案 0 :(得分：6)

简短回答是您需要手动将[XmlInclude(typeof(SequencePoint))]添加到MethodPoint课程中：

[System.CodeDom.Compiler.GeneratedCodeAttribute("xsd", "4.0.30319.33440")]
[System.SerializableAttribute()]
[System.Diagnostics.DebuggerStepThroughAttribute()]
[System.ComponentModel.DesignerCategoryAttribute("code")]
[System.Xml.Serialization.XmlTypeAttribute(AnonymousType=true)]
[XmlInclude(typeof(SequencePoint))]
public partial class CoverageSessionModulesModuleClassesClassMethodsMethodMethodPoint {
    private string vcField;
    private string uspidField;
    private string ordinalField;
    private string offsetField;
    private string slField;
    private string scField;
    private string elField;
    private string ecField;
    private string becField;
    private string bevField;
    private string fileidField;
}

如果SequencePoint尚未继承，则还需要MethodPoint继承。

你需要这样做，因为当你使用xsd.exe从XML样本生成XSD ，然后依次使用c＃类时，它显然不会添加多态子类型属性当属性xsi:type="SomePolymoirphicSubType"出现在XML中时自动建立基类型，即使看起来应该如此。

解释如下。 xsi:type属性是{http://www.w3.org/2001/XMLSchema-instance}type的缩写，是w3c standard attribute，允许元素明确断言其类型，例如当它是预期元素类型的多态子类型时。 XmlSerializer supports this attribute并将使用它来确定要为这种多态类型反序列化的实际对象类型。但是，需要使用XmlIncludeAttribute提前通知所有可能类型的 。因此，如果我创建以下类型层次结构：

[XmlInclude(typeof(SequencePoint))]
public class MethodPoint
{
}

public class SequencePoint : MethodPoint
{
}

按如下方式序列化：

var test = new SequencePoint();

var serializer = new XmlSerializer(typeof(MethodPoint));
var sb = new StringBuilder();
using (var stream = new StringWriter(sb))
    serializer.Serialize(stream, test);

Console.WriteLine(sb);

我得到以下XML：

<MethodPoint 
 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 xmlns:xsd="http://www.w3.org/2001/XMLSchema" 
 xsi:type="SequencePoint" />

然后，如果我使用var serializer = new XmlSerializer(typeof(MethodPoint))反序列化它，我会返回SequencePoint，而不是它的基类。如果我使用xsd.exe为这些类生成模式，我得到：

<xs:schema elementFormDefault="qualified" xmlns:xs="http://www.w3.org/2001/XMLSchema">
  <xs:element name="MethodPoint" nillable="true" type="MethodPoint" />
  <xs:complexType name="MethodPoint" />
  <xs:complexType name="SequencePoint">
    <xs:complexContent mixed="false">
      <xs:extension base="MethodPoint" />
    </xs:complexContent>
  </xs:complexType>
  <xs:element name="SequencePoint" nillable="true" type="SequencePoint" />
</xs:schema>

注意xs:extension？这就是XSD如何表示多态子类型。然后，如果我向后运行xsd.exe以重新生成我的类，我得到：

[System.Xml.Serialization.XmlIncludeAttribute(typeof(SequencePoint))]
[System.CodeDom.Compiler.GeneratedCodeAttribute("xsd", "2.0.50727.3038")]
[System.SerializableAttribute()]
[System.Diagnostics.DebuggerStepThroughAttribute()]
[System.ComponentModel.DesignerCategoryAttribute("code")]
[System.Xml.Serialization.XmlRootAttribute(Namespace="", IsNullable=true)]
public partial class MethodPoint {
}

/// <remarks/>
[System.CodeDom.Compiler.GeneratedCodeAttribute("xsd", "2.0.50727.3038")]
[System.SerializableAttribute()]
[System.Diagnostics.DebuggerStepThroughAttribute()]
[System.ComponentModel.DesignerCategoryAttribute("code")]
[System.Xml.Serialization.XmlRootAttribute(Namespace="", IsNullable=true)]
public partial class SequencePoint : MethodPoint {
}

如您所见，XmlIncludeAttribute就在那里，结果类等同于原始类。到目前为止，一切都很完美。

但是，似乎在从示例XML文件推断出XSD时，xsd.exe并没有了解xsi:type属性的存在。例如，如果我从上面的普通XML创建XSD，结果是：

<xs:schema id="MethodPoint" xmlns="" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:msdata="urn:schemas-microsoft-com:xml-msdata">
  <xs:element name="MethodPoint" msdata:IsDataSet="true" msdata:UseCurrentLocale="true">
    <xs:complexType>
      <xs:choice minOccurs="0" maxOccurs="unbounded" />
    </xs:complexType>
  </xs:element>
</xs:schema>

多态子类型完全缺失。从此XSD生成的类将无法反序列化该XML。

因此，似乎使用xsd.exe从XML示例生成c＃类并不像从正确的XSD生成它们那样可靠。具体而言，在XML文件中出现xsi:type的情况下，您需要手动修复生成的类或生成的XSD以实现所需的层次结构。这可能是工具中的限制或错误。

（限制/错误也会出现在内部使用xsd.exe的{​​{3}}中。）

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