XML 架构验证 - 行号始终返回 0

Question

我正在使用以下代码根据架构验证 XML 文件。

Public Sub LoadXml(xmlFilePath As String, xsdFilePath As String)
    Dim doc As New XmlDocument()
    doc.Load(xmlFilePath)
    doc.Schemas.Add(Nothing, xsdFilePath)
    Dim errorBuilder As New XmlValidationErrorBuilder()
    doc.Validate(New ValidationEventHandler(AddressOf errorBuilder.ValidationEventHandler))
    Dim errorsText As List(Of String) = errorBuilder.GetErrors()
End Sub
End Class

Public Class XmlValidationErrorBuilder
Private _errors As New List(Of ValidationEventArgs)()

Public Sub ValidationEventHandler(ByVal sender As Object, ByVal args As ValidationEventArgs)
    If args.Severity = XmlSeverityType.Error Then
        _errors.Add(args)
    End If
End Sub

Public Function GetErrors() As List(Of String)
    If _errors.Count <> 0 Then
        Dim ErrorList As New List(Of String)

        For i As Integer = 0 To _errors.Count - 1
            Dim Message As String = _errors(i).Message
            Dim LineNumber As String = _errors(i).Exception.LineNumber
            Dim LinePosition As String = _errors(i).Exception.LinePosition
            Dim combineString = Message & "|" & LineNumber & "|" & LinePosition
            ErrorList.Add(combineString)
        Next
        Return ErrorList
    Else
        Return Nothing
    End If
End Function

任何验证错误都存储在 List(Of ValidationEventArgs) 中，并稍后由 GetErrors 函数处理。我的问题是 Exception.LineNumber 和 Exception.LinePosition 总是返回 0。如何获取错误的行号和行位置？

Answer 1

LineNumber 和 LinePosition 仅在 XmlDocument 初始加载时可用。如果您随后调用Validate，它们将不会被填充。原因是文档加载后已转换为对象图，不再维护源流中的定位信息；原来的“文本”版本已被丢弃。

要在加载时进行验证，您需要执行以下操作:

Private Shared Function GetSchemaErrors(fileName As String) As List(Of XmlSchemaException)
    Dim errors As New List(Of XmlSchemaException)()

    Dim settings As New XmlReaderSettings()
    settings.Schemas = New XmlSchemaSet()
    settings.Schemas.Add(Nothing, "Path to .xsd file")
    settings.ValidationType = ValidationType.Schema
    AddHandler settings.ValidationEventHandler,
        Sub(sender, args) errors.Add(args.Exception)

    Dim reader As XmlReader = XmlReader.Create(fileName, settings)
    Dim doc = New XmlDocument
    doc.Load(reader)

    Return errors
End Function