SYSTEM.XML

Serialize a VB class to a string

steve@4penny.net — Mon, 04 Apr 2011 22:45:32 GMT

Here is a simple code example showing how to take a VB Class object and us Xml.Serialization to turn it into an XML string. I had a little trouble finding this code because all the examples wanted to write the XML to disk using a StreamWriter… I needed it in memory as a string

The resulting string looks like this:

Code Snippet
 Public Module Module1
 
    Public Class Product
        'this is our simple class of 'product' that we'll create
        Public Property ProductID As String
        Public Property ProductName As String
        Public Property cost As Double
    End Class
    Public Sub Main()
 
        'to make it a little more interesting, we'll serialize an Array of Product
        'declare the array
        Dim oProducts(1) As Product
        'declare the product class
        Dim oProduct As Product
 
        'create the first product
        oProduct = New Product
        oProduct.ProductID = "1"
        oProduct.ProductName = "Hammer"
        oProduct.cost = 5.12
        oProducts(0) = oProduct
 
        'create the second product
        oProduct = New Product
        oProduct.ProductID = "2"
        oProduct.ProductName = "Chisel"
        oProduct.cost = 9.99
        oProducts(1) = oProduct
 
        'Serialize the array to a string
        Dim sw As New IO.StringWriter
        Dim oSerializer As New Xml.Serialization.XmlSerializer(oProducts.GetType)
        oSerializer.Serialize(sw, (oProducts))
        MsgBox(sw.ToString)
 
    End Sub
End Module
 

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Deserialize an XML document with a parent/child relationship

steve@4penny.net — Thu, 17 Mar 2011 20:53:28 GMT

In the last example we took a simple XML document and deserialized it into a class. This example takes that idea one step further. Our source XML document is a standard ‘order’ with an Order Header and Order Detail sections. The class that we’re going to send it into needs to have a Generic List (of Item) to hold the order details.

Also, in the last example each item in the class was decorated with an directive. In this example we’ve remove those and placed a directive at the top of the class.

Also note that the was applied to the OrderNumber property, and it got correctly picked up as an attribute in the XML document

Code Snippet
 Imports System.Xml.Serialization
Imports Microsoft.VisualBasic
 
Public Class Form2
 
    Private Sub Form2_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
        Try
            ' Declare an object variable of the type to be deserialized.
            Dim i As Order
 
            'Create an instance of the XmlSerializer specifying type and namespace.
            'the 'OrderedItem' class is below
            Dim serializer As New XmlSerializer(GetType(Order))
 
            'open an XmlReader from a string
            'the getXMLDoc function returns an XML document in string format
            Dim reader As System.Xml.XmlReader = System.Xml.XmlReader.Create(New System.IO.StringReader(getXMLDoc))
 
            ' Use the Deserialize method to restore the object's state.
            i = CType(serializer.Deserialize(reader), Order)
 
            ' Write out the properties of the object.
            Console.WriteLine("Item Name: " & i.OrderNumber)
            Console.WriteLine("Item Desc: " & i.CustomerNumber)
 
        Catch ex As Exception
            MsgBox(ex.Message)
        End Try
 
 
    End Sub
 
    Function getXMLDoc() As String
        Dim xElement As XElement
        xElement = <Order OrderNumber="ORD002">
                       <CustomerNumber>CUST001CustomerNumber>
                       <Items>
                           <Item>
                               <ItemName>WidgetItemName>
                               <Quantity>1Quantity>
                               <UnitPrice>9UnitPrice>
                           Item>
                           <Item>
                               <ItemName>WidgetItemName>
                               <Quantity>10Quantity>
                               <UnitPrice>2.3UnitPrice>
                           Item>
                       Items>
                   Order>
 
        Return xElement.ToString
 
    End Function
End Class
 
'This is the class that will be deserialized.
<Serializable()> _
Public Class Order
    <XmlAttribute()> _
    Public OrderNumber As String
 
    Public CustomerNumber As String
    Public Items As List(Of Item)
 
End Class
 
<Serializable()> _
Public Class Item
    Public ItemName As String
    Public Quantity As Integer
    Public UnitPrice As Decimal
End Class
 

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Deserialize an XML document (from a string to a class)

steve@4penny.net — Thu, 17 Mar 2011 20:07:52 GMT

I get to see quite a bit of XML, and my path in the past has always been to use LINQ to iterate through the document and read it into a class. Then I’d use the class to do whatever work I need to do.

This code takes advantage of the XmlSerializer.Deserialize method.

To run this code, create a Windows Forms application and drop this code into the form code behind. It is complete and should run unmodified.

Note that the OrderedItem class and the getXMLDoc function both make use of namespaces for two of the elements, so we show how to code this both with and without namespace references.

Code Snippet
 Imports System.Xml.Serialization
Imports Microsoft.VisualBasic
 
Public Class Form1
 
    Private Sub Form1_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
        Try
            ' Declare an object variable of the type to be deserialized.
            Dim i As OrderedItem
 
            'Create an instance of the XmlSerializer specifying type and namespace.
            'the 'OrderedItem' class is below
            Dim serializer As New XmlSerializer(GetType(OrderedItem))
 
            'open an XmlReader from a string
            'the getXMLDoc function returns an XML document in string format
            Dim reader As System.Xml.XmlReader = System.Xml.XmlReader.Create(New System.IO.StringReader(getXMLDoc))
 
            ' Use the Deserialize method to restore the object's state.
            i = CType(serializer.Deserialize(reader), OrderedItem)
 
            ' Write out the properties of the object.
            Console.WriteLine("Item Name: " & i.ItemName)
            Console.WriteLine("Item Desc: " & i.Description)
 
        Catch ex As Exception
            MsgBox(ex.Message)
        End Try
 
 
    End Sub
 
    Function getXMLDoc() As String
        Dim xElement As XElement
        xElement = <OrderedItem xmlns:money="http://www.devshed.us">
                       <ItemName>WidgetItemName>
                       <Description>Regular WidgetDescription>
                       <Quantity>10Quantity>
                       <money:UnitPrice>2.3money:UnitPrice>
                       <money:LineTotal>23money:LineTotal>
                   OrderedItem>
 
        Return xElement.ToString
 
    End Function
End Class
 
' This is the class that will be deserialized.
Public Class OrderedItem
    <XmlElement()> _
    Public ItemName As String
 
    <XmlElement()> _
    Public Description As String
 
    <XmlElement()> _
    Public Quantity As Integer
 
    <XmlElement(Namespace:="http://www.devshed.us")> _
    Public UnitPrice As Decimal
 
    <XmlElement(Namespace:="http://www.devshed.us")> _
    Public LineTotal As Decimal
    ' A custom method used to calculate price per item.
    Public Sub Calculate()
        LineTotal = UnitPrice * Quantity
    End Sub
End Class
 

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SYSTEM.XML: InsertAfter

steve@4penny.net — Tue, 12 Oct 2010 20:14:02 GMT

InsertAfter gave me fits today. This code:

    Sub test2()
        Try
            'The reference node is not a child of this node
            Dim xmlDoc As New XmlDocument
            xmlDoc.LoadXml("1")

            Dim xnNode1 As XmlNode = xmlDoc.SelectSingleNode("root/doc/node1")
            Dim xnNode2 As XmlNode = xmlDoc.CreateElement("node2")
            xnNode2.InnerXml = "steve"
            xmlDoc.InsertAfter(xnNode2, xnNode1)

            MsgBox(xmlDoc.ToString)
        Catch ex As Exception
            MsgBox(ex.Message)
        End Try
    End Sub

Always returns ‘The reference node is not a child of this node’. Grrr.

This technique works, though:

    Sub test()
        Try
            'The reference node is not a child of this node
            Dim xmlDoc As New XmlDocument
            xmlDoc.LoadXml("1")

            Dim xnNode1 As XmlNode = xmlDoc.SelectSingleNode("root/doc/node1")
            Dim xnParent As XmlNode = xnNode1.ParentNode

            Dim xnNode2 As XmlNode = xmlDoc.CreateElement("node2")
            xnNode2.InnerXml = "steve"
            xnParent.InsertAfter(xnNode2, xnNode1)

            MsgBox(xmlDoc.ToString)
        Catch ex As Exception
            MsgBox(ex.Message)
        End Try
    End Sub

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SYSTEM.XML: Query an attribute within a node

steve@4penny.net — Mon, 13 Sep 2010 17:39:49 GMT

Task:

Given this XML document:

xml version="1.0" encoding="utf-8"?>
<root>
  <currentProfile>defaultcurrentProfile>
  <profiles>
    <profile name="default">
      <scriptFolder>C:\myScriptsscriptFolder>
    profile>
    <profile name="special">
      <scriptFolder>C:\specialScriptsscriptFolder>
    profile>
  profiles>
root>

We need to get the value of the ‘scriptFolder’ node for the ‘default’ profile.

Here’s the code:

Imports System.Xml

Dim xmldoc As New XmlDocument
xmldoc.Load(Application.StartupPath & "\Profiles.xml")

Dim strQuery As String
strQuery = "root/profiles/profile[@name='default']/scriptFolder"

Dim xnScriptFolder As XmlNode = xmldoc.SelectSingleNode(strQuery)

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XmlDocument: Loop through a document and move an attribute to a node

steve@4penny.net — Sat, 21 Aug 2010 16:40:21 GMT

Today’s task has to do with an XML document that has the form:

<OutboundReports>
    <InvoiceNotice>
        <InvoiceNoticeHeader InvoiceDate="20100607" InvoiceType="Invoice" invoiceID="60252726" purpose="PR">
        InvoiceNoticeHeader>
    InvoiceNotice>
    <InvoiceNotice>
        <InvoiceNoticeHeader InvoiceDate="20100607" InvoiceType="Invoice" invoiceID="60252727" purpose="PR">
        InvoiceNoticeHeader>
    InvoiceNotice>
OutboundReports>

We need to move the InvoiceDate, InvoiceType, and invoiceID attributes to ‘nodes’, so that our integration program will see them, the current version will not read attributes. Here’s what we want it to look like in the end:

<OutboundReports>
    <InvoiceNotice>
        <InvoiceNoticeHeader InvoiceDate="20100607" InvoiceType="Invoice" invoiceID="60252726" purpose="PR">
            <InvoiceDate>20100607InvoiceDate>
            <InvoiceType>InvoiceInvoiceType>
            <InvoiceID>60252726InvoiceID>
        InvoiceNoticeHeader>
    InvoiceNotice>
    <InvoiceNotice>
        <InvoiceNoticeHeader InvoiceDate="20100607" InvoiceType="Invoice" invoiceID="60252727" purpose="PR">
            <InvoiceDate>20100607InvoiceDate>
            <InvoiceType>InvoiceInvoiceType>
            <InvoiceID>60252726InvoiceID>
        InvoiceNoticeHeader>
    InvoiceNotice>
OutboundReports>

Here’s the code:

            'Load the document
            Dim xmlDoc As New XmlDocument
            xmlDoc.Load(txtSourceFile.Text)
            'loop through the xml document
            Dim elemList As XmlNodeList = xmlDoc.GetElementsByTagName("InvoiceNoticeHeader")
            Dim i As Integer
            Dim MyCultureInfo As System.Globalization.CultureInfo = New System.Globalization.CultureInfo("en-US")
            For i = 0 To elemList.Count - 1
                Dim strInvoiceDate As String = elemList(i).Attributes("InvoiceDate").InnerXml
                Dim dtInvoiceDate As Date = Date.ParseExact(strInvoiceDate, "yyyyMMdd", MyCultureInfo)
                Dim xelemInvoiceDate As XmlElement = xmlDoc.CreateElement("InvoiceDate")
                xelemInvoiceDate.InnerText = strInvoiceDate
                elemList(i).AppendChild(xelemInvoiceDate)
                Dim strInvoiceType As String = elemList(i).Attributes("InvoiceType").InnerXml
                Dim xelemrInvoiceType As XmlElement = xmlDoc.CreateElement("InvoiceType")
                xelemrInvoiceType.InnerText = strInvoiceType
                elemList(i).AppendChild(xelemrInvoiceType)
                Dim strInvoiceID As String = elemList(i).Attributes("invoiceID").InnerXml
                Dim xelemInvoiceID As XmlElement = xmlDoc.CreateElement("InvoiceID")
                xelemInvoiceID.InnerText = strInvoiceID
                elemList(i).AppendChild(xelemInvoiceID)
            Next i
            xmlDoc.Save(Me.txtDestinationFile.Text)

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SYSTEM.XML: Update a single node in a document

steve@4penny.net — Thu, 17 Jun 2010 18:04:39 GMT

The task here is to use the SYSTEM.XML DOM and update a single node in a document. My document looks like this:

<eConnect xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
  <POPReceivingsType>
    <taUpdateCreateVendorRcd>
    taUpdateCreateVendorRcd>
    <taCreateVendorAddress>
    taCreateVendorAddress>
    <taPopRcptLineInsert_Items>
      <taPopRcptLineInsert>
        <PONUMBER>PO08/00012PONUMBER>
        <LOCNCODE>VA-PIEDMONTBLOCNCODE>
      taPopRcptLineInsert>
      <taPopRcptLineInsert>
        <PONUMBER>PO08/00012PONUMBER>
        <LOCNCODE>VA-PIEDMONTALOCNCODE>
      taPopRcptLineInsert>
    taPopRcptLineInsert_Items>
    <taPopRcptHdrInsert>
      <POPRCTNM>RC08/00028POPRCTNM>
      <POPTYPE>1POPTYPE>
      <BACHNUMB>MYBATCHBACHNUMB>
    taPopRcptHdrInsert>
  POPReceivingsType>
eConnect>

Here is a sample of code that will do the deed.

Imports System.Xml

        Dim xmlDoc As New XmlDocument
        xmlDoc.Load(Application.StartupPath & "\xmlfile1.xml")
        Dim xnBatch As XmlNode = xmlDoc.SelectSingleNode("eConnect/POPReceivingsType/taPopRcptHdrInsert/BACHNUMB")
        xnBatch.InnerXml = "NewBatch"
        MsgBox(xmlDoc.InnerXml)

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