单遍读取和验证 XML 与 C# 中引用的 XSD [英] Single-pass Read and Validate XML vs referenced XSD in C#

问题描述

我正在尝试从 XML 文件中读取数据，并根据它建议的 XSD 对其进行验证，并将其转换为单个数据结构(例如 XmlDocument).我有一个解决方案，但它需要 2 遍文件，我想知道是否有单遍解决方案.

I'm trying to read the data from an XML file, validating it against the XSD it suggests, into a single data structure (such as XmlDocument). I have a solution, but it requires 2 passes through the file, and I'm wondering if there's a single-pass solution.

MyBooks.xml:

<Books xmlns:xsi='http://www.w3.org/2001/XMLSchema-instance'
     xsi:noNamespaceSchemaLocation='books.xsd' id='999'>
    <Book>Book A</Book>
    <Book>Book B</Book>
</Books>

Books.xsd:

<xs:schema xmlns:xs='http://www.w3.org/2001/XMLSchema'
    elementFormDefault='qualified'
    attributeFormDefault='unqualified'>
    <xs:element name='Books'>
        <xs:complexType>
            <xs:sequence>
                <xs:element name='Book' type='xs:string' />
            </xs:sequence>
            <xs:attribute name='id' type='xs:unsignedShort' use='required' />
        </xs:complexType>
    </xs:element>
</xs:schema>

假设 MyBooks.xml 和 Books.xsd 在同一个目录中.

Let's say MyBooks.xml and Books.xsd are in the same directory.

验证:

//Given a filename pointing to the XML file
var settings = new XmlReaderSettings();

settings.ValidationType = ValidationType.Schema;

settings.ValidationFlags |= XmlSchemaValidationFlags.ProcessInlineSchema;
settings.ValidationFlags |= XmlSchemaValidationFlags.ProcessSchemaLocation;
settings.ValidationFlags |= XmlSchemaValidationFlags.ReportValidationWarnings;

settings.CloseInput = true;
settings.ValidationEventHandler += new ValidationEventHandler(ValidationCB);
//eg:
//private static void ValidationCB(object sender, ValidationEventArgs args)
//{ throw new ApplicationException(args.Message); }

using(var reader = XmlReader.Create(filename, settings))
{ while(reader.Read()) ; }

读入 XmlDocument:

XmlDocument x = new XmlDocument();
x.Load(filename);

当然，我可以在从 XmlReader 读取数据时收集节点，但如果可能的话，我宁愿自己不必这样做.有什么建议吗?

Sure, I could collect the nodes as the read from the XmlReader is taking place, but I'd rather not have to do it myself, if possible. Any suggestion?

提前致谢

推荐答案

您的解决方案非常接近；您需要做的是使用验证阅读器来加载您的 XML；这样一来，您的加载就完成了验证；验证错误不会阻止您加载文档.

You're very close with your solution; what you need to do is to use a validating reader to load your XML; this way the validation is done with your loading, in one pass; validation errors will not stop you from loading the document.

这些是我通常与 ValidateXml 辅助函数一起使用的高级步骤；这一切都从一个已编译的 XmlSchemaSet 开始:

These are the high level steps that I usually use with a ValidateXml helper function; it all starts with a compiled XmlSchemaSet:

public bool ValidateXml(XmlSchemaSet xset)

我设置了阅读器设置(你也这样做了):

I set the reader settings (which you did, too):

XmlReaderSettings settings = new XmlReaderSettings { ValidationType = ValidationType.Schema, Schemas = xset, ConformanceLevel = ConformanceLevel.Document };
settings.ValidationFlags |= XmlSchemaValidationFlags.ReportValidationWarnings;
// Use your helper class that collects validation events. 
XsdUtils.Utils.SmartValidationHandler svh = new XsdUtils.Utils.SmartValidationHandler(Paschi.Xml.DefaultResolver.Instance);
settings.ValidationEventHandler += svh.ValidationCallbackOne;

然后我得到一个读者:

XmlReader xvr = XmlReader.Create(filename, settings);

然后我读取了文件，它带来了验证:

Then I read the file, which brings the validation in:

XmlDocument xdoc = new XmlDocument();
xdoc.Load(xvr);

您的验证处理程序现在有了结果；我还要做的一件事是确保加载的文档元素实际上在 xml 模式集中具有相应的全局元素定义.

Your validation handler has the results now; one thing I also do is to ensure that the document element that was loaded, actually has a corresponding global element definition in the xml schema set.

XmlQualifiedName qn = XmlQualifiedName.Empty;
if (xdoc.DocumentElement != null)
{
        if (string.IsNullOrEmpty(xdoc.DocumentElement.NamespaceURI))
        {
              qn = new XmlQualifiedName(xdoc.DocumentElement.LocalName);
        }
        else
        {
               qn = new XmlQualifiedName(xdoc.DocumentElement.LocalName, xdoc.DocumentElement.NamespaceURI);
         }
}
return !(svh.HasError || qn.IsEmpty || (!xset.GlobalElements.Contains(qn)));

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