使用VBA解析XML文件

Question

我有一个XML文件,其结构类似于:

<egh_eval>
<eval_set>
    <eval_id>FLOAT</eval_id>
    <eval_d>
        <height>INT</height>
        <weight>INT</weight>
    </eval_d>
    <eval_e>
        <height>INT</height>
        <weight>INT</weight>
    </eval_e>
    <eval_cred>
        <credit>FLOAT</credit>
    </eval_cred>
</eval_set>

我需要解析完整的文件并将其放在表格中.(注意:eval_d和eval_e实际上每个都有超过一百个属性).我尝试使用MSXML2,但是当我尝试解析文件时,我遇到了问题.通过使用在回答如何在VBA填写Flash XML和VBA中解析XML我能到那里:

Dim fSuccess As Boolean
Dim oDoc As MSXML2.DOMDocument
Dim oRoot As MSXML2.IXMLDOMNode ' Level 0 egh_eval
Dim oChild As MSXML2.IXMLDOMNode ' Level 1 eval_set
Dim oChildren As MSXML2.IXMLDOMNode ' Level 2 eval_id, eval_d, eval_e, eval_cred


Dim domList As MSXML2.IXMLDOMNodeList

Set oDoc = New MSXML2.DOMDocument
oDoc.async = False
oDoc.validateOnParse = False

fSuccess = oDoc.Load(Application.CurrentProject.Path & "\file.xml")

Set oRoot = oDoc.documentElement
Set oChild = oRoot.childNodes(0)
Set oChildren = oChild.childNodes(0)

For i = 0 To oChild.childNodes.length - 1
    For y = 0 To oChildren.childNodes.length - 1
        MsgBox oChildren.nodeName & " : " & oChildren.nodeTypedValue
        oChildren.childNodes.nextNode
    Next
    oChild.childNodes.nextNode
Next

但是,它没有给我正确的值,而是让我在eval_id中浮动4次...

谢谢 !

编辑:我正在使用Microsoft Access 2002 SP3

Answer 1

你的循环都错了.不要使用计数循环.有For Each哪些将完全满足您的需求,而且它的可读性也更高.

Dim egh_eval As MSXML2.IXMLDOMNode
Dim eval_set As MSXML2.IXMLDOMNode
Dim eval_prop As MSXML2.IXMLDOMNode

Set egh_eval = oDoc.documentElement.childNodes(0)

For Each eval_set In egh_eval.childNodes
  If eval_set.nodeType = NODE_ELEMENT Then
    For Each eval_prop In eval_set.childNodes
      If eval_prop.nodeType = NODE_ELEMENT Then
        MsgBox eval_prop.nodeName & " : " & eval_prop.childNodes.length
      End If
    Next eval_prop
  End If
Next eval_set

使用childNodes时必须检查nodeType酒店.注释,文本节点等都将在子节点列表中,而不仅仅是元素节点.

考虑使用XPath来选择元素可能是个好主意.使用DOM方法执行此操作容易出错并且很麻烦.阅读IXMLDOMNode::selectNodes和IXMLDOMNode::selectSingleNode.

For Each eval_set In oDoc.selectNodes("/egh_eval/eval_set")
  Set eval_id = eval_set.selectSingleNode("eval_id")

  ' always check for empty search result!
  If Not eval_id Is Nothing Then
    MsgBox eval_id.text
    ' ...
  End If
Next eval_set

另外,一般情况下.这个:

fSuccess = oDoc.Load(Application.CurrentProject.Path & "\file.xml")

实际上既不是必要的也不是一个坏主意,因为你似乎永远不会检查它的价值fSuccess.更好:

Sub LoadAndProcessXml(path As String)
  Dim oDoc As MSXML2.DOMDocument

  If oDoc.Load(path) Then
    ProcessXmlFile oDoc
  Else
    ' error handling
  End If
End Sub

Sub ProcessXml(doc As MSXML2.DOMDocument) 
  ' Process the contents like shown above
End Sub

创建多个子/函数有几个优点

• 使错误处理更容易,因为每个函数只有一个目的.
• 您将需要更少的变量,因为您可以在函数参数中定义一些变量
• 代码将变得更易于维护,因为3个短函数比一个长函数做的更明显.