在 C# 中编译包含重定义的架构

Question

当读取包含 标签的架构并尝试使用架构集对其进行编译时，出现此异常：

'SchemaLocation' must successfully resolve if <redefine>
contains any child other than <annotation>

我尝试了许多解决方法，但均未成功，例如递归解析架构并将它们添加到架构中在编译之前设置，甚至通过添加它们作为参考来设置。架构仍然无法编译。尝试的示例（解析主 xsd，然后在调用此递归函数后尝试编译生成的“XmlSchemas”）：

private void AddRecursive (XmlSchemas xsds, XmlSchema schema)
{
    foreach (XmlSchemaExternal inc in schema.Includes) {
        String schemaLocation = null;
        schemaLocation = inc.SchemaLocation;
        XmlSchema xsd;
        using (FileStream stream = new FileStream (schemaLocation, FileMode.Open, FileAccess.Read)) {
            xsd = XmlSchema.Read (stream, null);
            xsds.Add (xsd);
            xsds.AddReference (xsd);
        }
        AddRecursive (xsds, xsd);
    }
}

处理此类架构的正确方法是什么？为什么模式编译器无法解析添加的模式本身？

Answer 1

使用基于流的重载读取 XML 架构的问题是，没有可供 XML 架构读取器使用的基本 uri。如果您的 xsd:redefine 在 schemaLocation 属性中使用相对 URI，则默认解析器将无法找到正在重新定义的架构 - 因此您会收到错误消息。

我为您提供以下配置来帮助您继续操作，至少让您了解其工作原理。将两个架构和测试脚本保存在同一文件夹中，更新脚本中的路径并运行 C# 脚本。它会给您以下输出：

QN: http://tempuri.org/XMLSchema.xsd:TRedefine, SourceUri: file:///D:/.../.../Redefine.xsd
QN: http://www.w3.org/2001/XMLSchema:anyType, SourceUri: 

如果您更新脚本以使用基于流的重载，您将从帖子中收到错误消息。

Error line 20:      xset.Add(XmlSchema.Read(File.Open    (@"D:\...\...\Redefine.xsd", FileMode.Open), null));
    'SchemaLocation' must successfully resolve if <redefine> contains any child other than     <annotation>.
'SchemaLocation' must successfully resolve if <redefine> contains any child other than     <annotation>.
Error Line 21: xset.Add(XmlSchema.Read(File.Open    (@"D:\...\...\Redefine.xsd", FileMode.Open), null));

基本架构：

<?xml version="1.0" encoding="utf-8" ?>
<xsd:schema targetNamespace="http://tempuri.org/XMLSchema.xsd"
    elementFormDefault="qualified"
    xmlns="http://tempuri.org/XMLSchema.xsd"
    xmlns:xsd="http://www.w3.org/2001/XMLSchema">
    <xsd:complexType name="TRedefine">
        <xsd:sequence>
            <xsd:element name="base" type="xsd:string"/>
        </xsd:sequence>
    </xsd:complexType>
</xsd:schema>

重新定义的架构：

<?xml version="1.0" encoding="utf-8"?>
<!--XML Schema generated by QTAssistant/XSR Module (http://www.paschidev.com)-->
<xsd:schema xmlns="http://tempuri.org/XMLSchema.xsd" attributeFormDefault="unqualified"     elementFormDefault="qualified" targetNamespace="http://tempuri.org/XMLSchema.xsd"     xmlns:xsd="http://www.w3.org/2001/XMLSchema">
    <!-- Put a full path here.
  <xsd:redefine schemaLocation="D:\...\...\Base.xsd">
    -->
    <xsd:redefine schemaLocation="Base.xsd">
        <xsd:complexType name="TRedefine">
            <xsd:complexContent>
                <xsd:extension base="TRedefine">
                    <xsd:sequence/>
                </xsd:extension>
            </xsd:complexContent>
        </xsd:complexType>
    </xsd:redefine>
</xsd:schema>

测试脚本：

using System;
using System.IO;
using System.Xml;
using System.Xml.Schema;
class Script
{
    public static void Main()
    {
        // Enter your code below
        // Generated by QTAssistant (http://www.paschidev.com)
        XmlSchemaSet xset = new XmlSchemaSet();

        // One way of doing using an XmlReader - it'll work with relative URIs.
        using(XmlReader reader = XmlReader.Create(@"D:\...\...\Redefine.xsd"))
        {
            xset.Add(XmlSchema.Read(reader, null));
        }

        // The other way, using stream, requires all external URIs - xsd:include,     xsd:import and xsd:redefine 
        // to be absolute
        //xset.Add(XmlSchema.Read(File.Open(@"D:\...\...\Redefine.xsd", FileMode.Open), null));

        xset.Compile();
        Console.WriteLine(xset.IsCompiled);
        foreach(XmlSchemaType type in xset.GlobalTypes.Values) 
        {
            Console.WriteLine("QN: {0}, SourceUri: {1}", type.QualifiedName,     type.SourceUri);
        }
    }
}

Answer 2

使用 XmlDocument 的相对路径的工作示例：

        XmlReaderSettings settings = new XmlReaderSettings();
        settings.ValidationType = ValidationType.Schema;
        // It won't add schemas without XmlUrlResolver
        settings.Schemas.XmlResolver = new XmlUrlResolver();
        // Optional namespace
        var namespace = null;
        settings.Schemas.Add(namespace, "absolutePath.xsd");

        using (XmlReader reader = XmlReader.Create(sourcePath, settings))
        {
            XmlDocument document= new XmlDocument();
            document.Load(reader);
            //...
        }