Read/Write XML File

The XML format is used a lot and often to changing info between applications or as configuration files on which it is indicated how pages/tables must be created or something else.

So it is very useful know how to manage, Read and Write them; let's see how.

XML files constist of data grouped per type using a hierarchy. Suppose to have, for example, an XML structured in this manner:

<?xml version="1.0"?>
<Root>

</IDElemento>

<string>"Libro"</string>

</ValoreElemento>

</Elemento>

</ElencoElementi>

</Root>

Legend (because it comes from the Italian site):

ElencoElementi = ElementsList

Elemento = Element

IDElemento = IDElement

ValoreElemento = ElementValue

Libro = Book

Suppose we'd like to put another Element who will have ID = "2" and the Value will be "Penna" (Pen). Suppose also that the file name is "element.xml" and it is stored in c:\temp. We'll write this code:

'************************************************

'***************** M A I N ************************

'************************************************

Dim objXMLDoc, oRootElement, oNodeElencoElementi, oNodeElemento
Dim oNodeElementoId, oNodeElementoVal, oNodeStrId, oNodeStrVal

Const myVar = "c:\temp\element.xml"
Const ID_ToAdd = "2"
Const ValueToAdd = "Penna"

       'MS XML DOM
       set objXMLDoc=CreateObject("Microsoft.XMLDOM")
       objXMLDoc.async="false"

'loading xml file ---> myVar
objXMLDoc.load(myVar)

       'the root element of the xml tree
        set oRootElement = objXMLDoc.documentElement


       'I set the first element after root that is <ElencoElementi>
       'under whom I have to insert <Elemento>
       set oNodeElencoElementi = oRootElement.ChildNodes.Item(0)

set oNodeElemento = objXMLDoc.createNode(1,"Elemento","")
oNodeElencoElementi.appendChild oNodeElemento

set oNodeElementoId = objXMLDoc.createNode(1,"IDElemento","")
oNodeElemento.appendChild oNodeElementoId

                    set oNodeStrId = objXMLDoc.createNode(1,"string","")
                    oNodeStrId.Text = ID_ToAdd
                    oNodeElementoId.appendChild oNodeStrId

set oNodeElementoVal = objXMLDoc.createNode(1,"ValoreElemento","")
oNodeElemento.appendChild oNodeElementoVal

                     set oNodeStrVal = objXMLDoc.createNode(1,"string","")
                     oNodeStrVal.Text = ValueToAdd
                     oNodeElementoVal.appendChild oNodeStrVal

objXMLDoc.Save(myVar)

set oNodeStrVal             = Nothing
set oNOdeStrId              = Nothing
set oNodeElementoVal     = Nothing
set oNodeElementoId      = Nothing
set oNodeElemento         = Nothing
set oNodeElencoElementi = Nothing
set oRootElement           = Nothing
Set objXMLDoc              = Nothing

'************************************************

Il risultato sarà questo:

Let's see now how to read from an XML file. Suppose we want to read from the above file all "IDElemento".

To do this is possible to use the getElementsByTagName method of the oRootElement object. We'll do a cycle for all oRootElement.ChildNodes and show the "IDElemento" Value.

'*************************************************

'********************* M A I N ********************

'*************************************************

Dim objXMLDoc, oRootElement, oNodeElementoId, i

Const myVar = "c:\temp\element.xml"

'MS XML DOM
set objXMLDoc=CreateObject("Microsoft.XMLDOM")
objXMLDoc.async="false"

'loading xml file ---> myVar
objXMLDoc.load(myVar)

'the root element of the xml tree
set oRootElement = objXMLDoc.documentElement

set oNodeElementoID = oRootElement.getElementsByTagName("IDElemento")

for i = 0 to oRootElement.childNodes.Length

msgbox oNodeElementoID(i).childNodes(0).Text

set oRootElement = Nothing

'*************************************************

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