Question

我正在编写一个需要验证XML文件的WPF应用程序。我有以下类来针对一个或多个XSD文件验证XML：

public class XSDValidator
{
    public List<XmlSchema> Schemas { get; set; }
    public List<String> Errors { get; set; }
    public List<String> Warnings { get; set; }

    public XSDValidator()
    {
        Schemas = new List<XmlSchema>();
    }

    /// <summary>
    /// Add a schema to be used during the validation of the XML document
    /// </summary>
    /// <param name="schemaFileLocation">The file path for the XSD schema file to be added for validation</param>
    /// <returns>True if the schema file was successfully loaded, else false (if false, view Errors/Warnings for reason why)</returns>
    public bool AddSchema(string schemaFileLocation)
    {
        // Reset the Error/Warning collections
        Errors = new List<string>();
        Warnings = new List<string>();

        XmlSchema schema;

        if (!File.Exists(schemaFileLocation))
        {
            throw new FileNotFoundException("The specified XML file does not exist", schemaFileLocation);
        }

        using (var fs = new FileStream(schemaFileLocation, FileMode.Open))
        {
            schema = XmlSchema.Read(fs, ValidationEventHandler);
        }

        var isValid = !Errors.Any() && !Warnings.Any();

        if (isValid)
        {
            Schemas.Add(schema);
        }

        return isValid;
    }

    /// <summary>
    /// Perform the XSD validation against the specified XML document
    /// </summary>
    /// <param name="xmlLocation">The full file path of the file to be validated</param>
    /// <returns>True if the XML file conforms to the schemas, else false</returns>
    public bool IsValid(string xmlLocation)
    {
        if (!File.Exists(xmlLocation))
        {
            throw new FileNotFoundException("The specified XML file does not exist", xmlLocation);
        }

        using (var xmlStream = new FileStream(xmlLocation, FileMode.Open))
        {
            return IsValid(xmlStream);
        }
    }

    /// <summary>
    /// Perform the XSD validation against the supplied XML stream
    /// </summary>
    /// <param name="xmlStream">The XML stream to be validated</param>
    /// <returns>True is the XML stream conforms to the schemas, else false</returns>
    private bool IsValid(Stream xmlStream)
    {
        // Reset the Error/Warning collections
        Errors = new List<string>();
        Warnings = new List<string>();

        var settings = new XmlReaderSettings
        {
            ValidationType = ValidationType.Schema
        };
        settings.ValidationEventHandler += ValidationEventHandler;

        foreach (var xmlSchema in Schemas)
        {
            settings.Schemas.Add(xmlSchema);
        }

        var xmlFile = XmlReader.Create(xmlStream, settings);

        while (xmlFile.Read()) { }

        return !Errors.Any() && !Warnings.Any();
    }

    private void ValidationEventHandler(object sender, ValidationEventArgs e)
    {
        switch (e.Severity)
        {
            case XmlSeverityType.Error:
                Errors.Add(e.Message);
                break;
            case XmlSeverityType.Warning:
                Warnings.Add(e.Message);
                break;
        }
    }
}

以上代码是开源的，可以找到here。现在，它被称为：

var validator = new XSDValidator();
validator.AddSchema(@"C:\code\xml\books.xsd");

foreach (CheckableListItem file in FileFullPathChecklist)
{
    if (file.IsChecked)
    {
        if (validator.IsValid(file.Filename)) 
        {
            ValidatedXMLFiles++;
        }
    }
}

在我测试XSD验证时，我使用了4个XML文件：其中一个books.xml对应于硬编码模式books.xsd。其他三个是我从其他来源提取的随机XML文件，我已经验证它们对books.xsd无效。但是，在运行代码时，ValidatedXMLFiles显示的值为4而不是1。

我已经从XSDValidator课程中验证了我能想到的内容;我尝试手动向Errors添加随机字符串，IsValid在这种情况下返回false。我认为有趣的一件事是，当我尝试将模式文件名更改为不存在的内容时，抛出TargetInvocationException而不是我期望的FileNotFoundException。我不知道这是否意味着什么，但这是我见过的唯一奇怪的行为。任何人都可以提供任何帮助吗？

Answer 1

您假设验证引擎将自动知道使用books.xsd架构来验证所有xml文件。

这不正确。 xml需要告诉验证器应该对哪个XSD进行验证。

要指明这一点，请在xml文档中设置xmlns属性。

例如：

<MyXml xmlns="http://MySchemaNamespace">
    ...
</MyXml>

架构：

<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" 
           targetNamespace="http://MySchemaNamespace" 
           xmlns="http://MySchemaNamespace" 
           elementFormDefault="qualified">
    ...
</xs:schema>

否则，XML的唯一标准是“有效”，即它的形成良好。

需要帮助在C＃中针对XSD验证XML

1 个答案: