了解xml结构的xml文件类型的最佳方法

Question

I want to read a xml file, and based on some xml structures I already know recognize the type of xml ( xml 1, xml 2 or xml 3 )

for example, I know 3 xml structures:

xml 1

<?xml version="1.0"?>
<OS>
  <Info>
   ...
  </Info>
</OS>

xml 2

<?xml version="1.0" encoding="UTF-8"?>
<SaData Version="2">
  <Cli>
  ...
  </Cli>
</SaData>

xml 3

<?xml version="1.0" encoding="UTF-8"?>
<Init>
     <Danit>
     ...
     </Danit>
</Init>

So far I have a class XMLBrandRecognitionNode that acts as a string enum for list of xmlTypes (I did it using a list because the number of xml types could grow, for now there are only 3 types)

Public Class XMLBrandRecognitionNode
        Private Key As String
        Public Shared ReadOnly xml1 As XMLBrandRecognitionNode = New XMLBrandRecognitionNode("/OS/Info")
        Public Shared ReadOnly xml2 As XMLBrandRecognitionNode = New XMLBrandRecognitionNode("/SaData/Cli")
        Public Shared ReadOnly xml3 As XMLBrandRecognitionNode = New XMLBrandRecognitionNode("/Init/Danit")
        Private Sub New(ByVal key As String)
            Me.Key = key
        End Sub
        Public Overrides Function ToString() As String
            Return Me.Key
        End Function
    End Class

And then I populate the list as:

Dim recognitionList As New List(Of XMLBrandRecognitionNode)
recognitionList.Add(XMLTypeN.xml1)
recognitionList.Add(XMLTypeN.xml2)
recognitionList.Add(XMLTypeN.xml3)

Now the part to classify the file ( xml1,xml2,xml3 )

Dim m_xmld As XmlDocument
m_xmld = New XmlDocument()
m_xmld.Load("myXML.xml")

However I do not know the best way to classify the type, I was thinking on doing a loop and based on the list of nodes that I get return the type

For Each o As XMLBrandRecognitionNode In recognitionList
   Try
        child_nodes = m_xmld.GetElementsByTagName(o.ToString)
        'maybe a condition or something...

   Catch ex As Exception
         Continue For
   End Try
Next

What would be the correct way to reckon a xml file type?

Answer 1

There is XML Schema Definition , which is a standard way to describe the structure of your XML. Create one XSD for each XML type and then you can test an XML document against each of your XSD to know which schema the XML conform to.

For simple scenario though, you might want to just write your own simple logic to classify your XML documents.

This is one possible way. The method will return True and set the xmlType to the correct type if XML structure is recognized by one of the patterns , else the method simply return False :

Public Function CheckXmlType(doc As XmlDocument, ByRef xmlType As String) As Boolean
    xmlType = "not recognized"
    'you can change this to dictionary(of enum, string) if you like'
    Dim patterns = New Dictionary(Of String, String)()
    patterns.Add("type1", "/OS/Info")
    patterns.Add("type2", "/SaData/Cli")
    patterns.Add("type3", "/Init/Danit")
    For Each p In patterns
        Dim test = doc.SelectSingleNode(p.Value)
        If test IsNot Nothing
            xmlType = p.Key
            Return True
        End If
    Next

    Return False
End Function

And then you can use it like so :

Dim m_xmld As XmlDocument
m_xmld = New XmlDocument()
m_xmld.Load("myXML.xml")

Dim xmlType As String = ""
If m_xmld.CheckXmlType(xmlType)
    'this should print type1/type2/type3 according to the content of myXML.xml'
    Console.WriteLine(xmlType)
Else
    Console.WriteLine("XML type is not recognized")
End If