读取 XML 文件时如何控制和获取特定数据

Question

下午好， 我有这个 XML 文件：

<SpectraMagicNX_data>
    <data_set version="2" cdate="2020-12-10T11:34:52+00:00" observer="10">
        <sample>
            <group name="Test1">
                <item name="article">OA</item>
                <item name="number">1</item>
                <item name="state:">Fail</item>
            </group>
            <group name="Test2">
                <item name="article">0B</item>
                <item name="number">1</item>
                <item name="state:">Aprove</item>
            </group>
        </sample>
    </data_set>
</SpectraMagicNX_data>`````

我希望当article 值等于0B 时，显示state 值。 批准在这种情况下

代码

        Do While (reader.Read())
            Select Case reader.NodeType
                Case XmlNodeType.Element
                    If reader.HasAttributes Then 'Se existirem atributos
                        While reader.MoveToNextAttribute()
                            If reader.Value = "OA" Then
                                MsgBox(reader.Value)
                            End If
                        End While
                    End If
                Case XmlNodeType.Text
                    MsgBox(reader.Value)
            End Select
        Loop`````

我不知道我是否使用了最好的方法，但我想要一些简单易懂的东西。

Reader.Value 基本上显示每个属性值，我无法控制。所以我想知道如何控制Group、item和他的值

Answer 1

使用多种功能的示例。它根据项目选择节点。然后它会获取该项目的状态。

    ' https://docs.microsoft.com/en-us/dotnet/standard/linq/linq-xml-overview
    Dim xe As XElement
    ' xe = XElement.Load("path to XML here") 'for production use this
    'for testing use literal
    xe = <SpectraMagicNX_data>
             <data_set version="2" cdate="2020-12-10T11:34:52+00:00" observer="10">
                 <sample>
                     <group name="Test1">
                         <item name="article">OA</item>
                         <item name="number">1</item>
                         <item name="state:">Fail</item>
                     </group>
                     <group name="Test2">
                         <item name="article">0B</item>
                         <item name="number">1</item>
                         <item name="state:">Aprove</item>
                     </group>
                 </sample>
             </data_set>
         </SpectraMagicNX_data>

    ' select the first <group> that has an item with a 
    '  name attribute="article" and value of OA

    Dim ie As IEnumerable(Of XElement)
    ' use LINQ
    ie = From el In xe...<group>.<item>
          Where el.@name = "article" AndAlso el.Value = "OA"
          Select el.Parent Take 1

    If ie.Count = 1 Then
        Dim ItemState As String
        ItemState = (From el In ie(0).Elements
                     Where el.@name = "state:"
                     Select el.Value).FirstOrDefault.ToString
        Stop 'look at ItemState
    End If