在VB6中使用Sax解析编辑和编写XML

Question

所以我试图在 VB6 中使用 SAX 解析来编辑一个 xml（输出是一个 xml）（对于一个古老的 COM 组件）。我更喜欢使用 DOM 解析，但 xml 的大小（可能超过 20MB）迫使我使用 SAX。我对 VB6 比较陌生，而且我在 SAX 解析方面没有经验。我在网上环顾四周，但即使是我找到的最好的资源 (http://www.developerfusion.com/article/84405/sax-and-vb-6/) 也让我对如何将孙子标签与现有属性结合起来知之甚少为重命名的标签创建一个更长的属性。

我有基本的框架设置（如链接网站所示）。我想我可能可以将大部分繁重的工作限制在两个或三个子过程中（_startDocument 中的前四行，使用 _startElement 获取描述标记，使用 endElement 将描述放入函数标记中）。然而，我缺乏 VB6/SAX 知识真的让我很伤心。任何帮助将不胜感激。

这是 XML 现在的样子；

<errordetails>
<error desc=”Count: 2”/>
<error desc=”System: System X”/>
<error desc=”Reason: Reason X”/>
   <functions>
      <function name=”x1” Description=”y1”>
         <violations count="2">
            <violation><source>admin</source><description>the first reason</description></violation>
            <violation><source>admin</source><description>the second reason</description></violation>
         </violations>  
      </function>
      <function name=”x2” Description=”y2”>
         <violations count="1">
           <violation><source>admin</source><description>another reason</description></violation>
        </violations>   
      </function>
   </functions>
</errordetails>

这是我希望 xml 的样子；

<errordetails>
<error desc=”Count: 2”/>
<error desc=”System: System X”/>
<error desc=”Reason: Reason X”/>
<error desc=”FunctionName: x1, FunctionDescription: y1, FunctionReason: the first reason, FunctionReason: the second reason”/>
<error desc=”FunctionName: x2, FunctionDescription: y2, FunctionReason: another reason"/>
</errordetails>

Answer 1

你读过类似旧文章The Joy of SAX: a Visual Basic Sample的东西吗？

很难告诉你更多。 SAX 真的很简单，您只需要像对待任何 VB6 表单一样将其作为状态机来处理。这意味着您将编写的大部分逻辑都将管理状态，例如在通过事件提供给您时累积和发出转换后的数据。

Answer 2

我忘了在我的问题中提到，如果一个函数的违规次数大于 20，我只希望前 20 个描述为 FunctionReasons。 我在 sax 解析之外添加了前四行和最后一行。 我通过调用最后一个属性“Get XMLDoc_Function()”在另一个模块中获得输出。 这是我得到的；

Option Explicit

Implements IVBSAXContentHandler

Dim m_oContentHandler As IVBSAXContentHandler
Dim m_wtr_Function As MXXMLWriter40
Dim m_oAttributes As MSXML2.SAXAttributes
Dim m_DOM As MSXML2.DOMDocument40

Dim m_sAttribute As String
Dim m_sFunctionName As String
Dim m_sFunctionDescription As String
Dim m_sFunctionReason As String
Dim m_sFunctionReasonCount As Integer

Dim isDescription As Boolean




Private Sub Class_Initialize()
    Set m_wtr_Function = New MXXMLWriter40
    m_wtr_Function.omitXMLDeclaration = True
    Set m_oContentHandler = m_wtr_Function
    Set m_DOM = New MSXML2.DOMDocument40
    m_DOM.setProperty "SelectionLanguage", "XPath"
    m_sFunctionReasonCount = 0
End Sub

Private Sub Class_Terminate()
    Set m_wtr_Function = Nothing
    Set m_oContentHandler = Nothing
    Set m_oAttributes = Nothing
    Set m_DOM = Nothing
End Sub

Private Sub IVBSAXContentHandler_characters(strChars As String)
    If isDescription Then
        If m_sFunctionReasonCount < 20 Then
            m_sFunctionReason = ", FunctionReason: " & strChars
            m_sAttribute = m_sAttribute & m_sFunctionReason
            m_sFunctionReasonCount = m_sFunctionReasonCount + 1
            isDescription = False
        End If
    End If
End Sub

Private Property Set IVBSAXContentHandler_documentLocator(ByVal RHS As MSXML2.IVBSAXLocator)

End Property

Private Sub IVBSAXContentHandler_endDocument()

End Sub

Private Sub IVBSAXContentHandler_endElement(strNamespaceURI As String, strLocalName As String, strQName As String)

    Select Case strQName
        Case "function"
            m_oAttributes.addAttribute "", "desc", "desc", "xs:string", m_sAttribute
            m_oContentHandler.startElement strNamespaceURI, "error", "error", m_oAttributes
            m_oContentHandler.endElement strNamespaceURI, "error", "error"
            m_sAttribute = ""
            m_sFunctionReasonCount = 0
    End Select

End Sub

Private Sub IVBSAXContentHandler_endPrefixMapping(strPrefix As String)

End Sub

Private Sub IVBSAXContentHandler_ignorableWhitespace(strChars As String)

End Sub

Private Sub IVBSAXContentHandler_processingInstruction(strTarget As String, strData As String)

End Sub

Private Sub IVBSAXContentHandler_skippedEntity(strName As String)

End Sub

Private Sub IVBSAXContentHandler_startDocument()

    m_oContentHandler.startDocument

End Sub



Private Sub IVBSAXContentHandler_startElement(strNamespaceURI As String, strLocalName As String, strQName As String, ByVal oAttributes As MSXML2.IVBSAXAttributes)

    Select Case strQName
        Case "functions"
            'do nothing

        Case "function"
            Set m_oAttributes = New SAXAttributes40
            m_sFunctionName = oAttributes.getValueFromQName("name")
            m_sAttribute = "FunctionName: " & m_sFunctionName
            m_sFunctionDescription = oAttributes.getValueFromQName("Description")
            m_sAttribute = m_sAttribute & ", FunctionDescription: " & m_sFunctionDescription

        Case "description"
            isDescription = True

    End Select

End Sub


Private Sub IVBSAXContentHandler_startPrefixMapping(strPrefix As String, strURI As String)

End Sub

Public Property Get XMLDoc_Function() As Variant
    XMLDoc_Function = m_wtr_Function.output
End Property