Imports System

Imports System.Collections.Generic

Imports System.Collections

Imports System.IO

Imports System.Text

Imports System.Linq

​

Imports System.Xml.Serialization

Imports System.Xml

Imports System.Xml.Linq

​

 ' https://stackoverflow.com/questions/76506717/order-of-data-read-from-xml

​

Public Module Module1   

    Public Sub Main()

        Console.WriteLine("Environment version: " & Environment.Version.ToString() & Environment.NewLine)

​

        Dim xml as String = GetXml()

​

        Dim filename = "Question76506717.xml"

        File.WriteAllText(filename, xml)

        Dim test = DeserializeFromFile(Of XmlTest)(filename)

​

        For Each item in test.TypeList

            Select Case item.GetType()

                Case GetType(Type1)

                    Console.WriteLine("Type is type 1, value is {0}.", item.Tekst)

                Case GetType(Type2)

                    Console.WriteLine("Type is type 3, value is {0}.", item.Tekst)

                Case GetType(Type3)

                    Console.WriteLine("Type is type 3, value is {0}.", item.Tekst)

                Case Else

                    Throw New Exception(String.Format("Unknown type {0}", item.GetType()))

            End Select

        Next

​

        dim xml2 = test.GetXml()

​

        Console.WriteLine()

        Console.WriteLine("Deserialized and re-serialized {0}:", test)

        Console.Writeline(xml2)

​

        File.Delete(filename)

    End Sub

​

    Function GetXml() As String

        Dim xml as String = <xmltest>

    <type1>

        <tekst>ABC</tekst>

    </type1>

    <type2>

        <tekst>DEF</tekst>

    </type2>

    <type1>

        <tekst>GHI</tekst>

    </type1>

    <type2>

        <tekst>JKL</tekst>

    </type2>

    <type3>

        <tekst>MNO</tekst>

    </type3>

</xmltest>.ToString()

        Return xml

    End Function

​

    Public Function DeserializeFromFile(Of T)(filename As String) As T

        Using stream = File.OpenRead(filename)

            Return DirectCast(New XmlSerializer(GetType(T)).Deserialize(stream), T)

        End Using

    End Function

End Module

​

​

' The root object with the polymorphic list corresponding to the possible types 

<XmlRoot("xmltest")> 

Public Class XmlTest

    <XmlElement("type1", GetType(Type1)), XmlElement("type2", GetType(Type2)), XmlElement("type3", GetType(Type3))>     

    Public Property TypeList As List(Of TypeBase) = New List(Of TypeBase) ()

End Class

​

' The <TypeN> polymorphic type hierarchy

Public Class TypeBase 

    <XmlElement("tekst")>

    Public Property Tekst As String

End Class

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<XmlType("type1")>

Public Class Type1 

    Inherits TypeBase

End Class

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<XmlType("type2")>

Public Class Type2

    Inherits TypeBase

End Class

​

<XmlType("type3")>

Public Class Type3 

    Inherits TypeBase

End Class

​

Public Module XmlSerializationHelper

    <System.Runtime.CompilerServices.Extension> _

    Public Function LoadFromXML(Of T)(xmlString As String) As T

        Using reader As New StringReader(xmlString)

            Return DirectCast(New XmlSerializer(GetType(T)).Deserialize(reader), T)

        End Using

    End Function

​

    <System.Runtime.CompilerServices.Extension> _

    Public Function GetXml(Of T)(obj As T, Optional omitStandardNamespaces As Boolean = False) As String

        Dim ns As XmlSerializerNamespaces = Nothing

        If omitStandardNamespaces Then

            ns = New XmlSerializerNamespaces()

                ' Disable the xmlns:xsi and xmlns:xsd lines.

            ns.Add("", "")

        End If

        Return obj.GetXml(ns)

    End Function

​

    <System.Runtime.CompilerServices.Extension> _

    Public Function GetXml(Of T)(obj As T, ns as XmlSerializerNamespaces) As String

        Using textWriter = New StringWriter()

            Dim settings = New XmlWriterSettings() With { _

                .Indent = True _

            }

            ' For cosmetic purposes.

            Using xmlWriter = System.Xml.XmlWriter.Create(textWriter, settings)

                Dim serializer as New XmlSerializer(obj.GetType()) 

                serializer.Serialize(xmlWriter, obj, ns)

            End Using

            Return textWriter.ToString()

        End Using

    End Function

​

    <System.Runtime.CompilerServices.Extension> _

    Public Function GetOuterXml(node as XmlNode, Optional indent as Boolean = true) as String

        Using textWriter = New StringWriter()

            ' For cosmetic purposes.

            Dim settings = New XmlWriterSettings() With { _

                .Indent = indent, _

                .OmitXmlDeclaration = true _

            }

            Using xmlWriter = System.Xml.XmlWriter.Create(textWriter, settings)

                node.WriteTo(xmlWriter)

            End Using

            Return textWriter.ToString()

        End Using       

    End Function

End Module

​