how to append child node to an existing xml file

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This is my code to create xmlfile
when i'm writing into it for first time it's working fine.when i'm inserting the content again it showing error only one root node is allowed.
The problem is when i'm additing nodes again i need to append it as a child node to the root node but i don't know how to do it.
Please help me to do this

VB

Sub CreateXmlFile()
       Dim objReportNodes As New System.Text.StringBuilder()
       Dim strDetails As String
       strDate = Request.Form("tBDate").ToString

       strTime = Request.Form("lBTime")

       strSubject = Request.Form("txtsubject")
       strAjanta = Request.Form("txtAjanta")
       strDetails = "<?xml version='1.0' encoding='windows-1252' ?>"
       strDetails &= "<Messages><Date>" & strDate & "</Date>" & _
                     "<Time>" & strTime & "</Time>" & _
                     "<Subject>" & strSubject & "</Subject>" & _
                     "<Ajanta>" & strAjanta & "</Ajanta>" & _
                     "</Messages>"
       objReportNodes.Append(strDetails)

       Dim objFile As System.IO.TextWriter = System.IO.File.AppendText("D:\XMLFile3.xml")

       objFile.WriteLine(objReportNodes)
       objFile.Close()
       objFile = Nothing
       objReportNodes = Nothing
       Call ReadXmlFile()
   End Sub

i tried using AppendChildNode() but here i'm using textwriter so it is not converting to system.xml.xmlnode

Posted 27-Jun-12 21:41pm

Agustee

Updated 27-Jun-12 21:57pm

v3

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2 solutions

Solution 1

As you're constructing your XML in a string, you can just use

objReportNodes.LoadXml(strDetails)

Edit: Working solution

VB

Dim objReportNodes As New Xml.XmlDocument
Dim strDetails As String

Dim strDate As Date ' = Request.Form("tBDate").ToString
Dim strTime As Date ' = Request.Form("lBTime")

Dim strSubject As String '= Request.Form("txtsubject")
Dim strAjanta As String ' = Request.Form("txtAjanta")
strDetails = "<Message><Date>" & strDate & "</Date>" & _
              "<Time>" & strTime & "</Time>" & _
              "<Subject>" & strSubject & "</Subject>" & _
              "<Ajanta>" & strAjanta & "</Ajanta>" & _
              "</Message>"

If IO.File.Exists("XMLFile3.xml") Then objReportNodes.Load("XMLFile3.xml") Else objReportNodes.LoadXml("<Messages></Messages>")
objReportNodes.FirstChild.InnerXml &= strDetails

objReportNodes.Save("XMLFile3.xml")

Posted 27-Jun-12 23:29pm

MarqW

Updated 28-Jun-12 0:13am

v2

Comments

Agustee 28-Jun-12 5:48am

objReportNode is a stringbuilder we can't use loadxml here.

MarqW 28-Jun-12 5:52am

My bad, I didn't read. I assumed it was an Xml.XmlDocument object (with the reference to Xml.XmlNode). Why not just use Xml.XmlDocument? It also has a save function for writing out to a text file. It actually lets you manipulate the Xml based on nodes too

Agustee 28-Jun-12 6:05am

i tried using that it shows me multiple root element.
what i want when i'm adding the content again it should added under root node.
Is it possible to do this with textwriter?

MarqW 28-Jun-12 6:12am

As indicated in Solution 2 - You need an a single root element (say called <messages>)
Then you can do XmlDoc.FirstChild.InnerXml &= strDetails (be sure to delete the line where you set "

Elangovan.N 28-Jun-12 6:13am

@Agustee
it will show multiple root element error,
because you should have only one root node (all-message) as i said in my solution.
in your case 'message' is the root node, and your code is inserting same <message> root node while appending.
This is not correct.

Agustee 28-Jun-12 8:02am

i used XPathNavigator to move to child node

MarqW 28-Jun-12 8:07am

You don't even use XmlDocument in that function, how can you use XPathNavigator?

Sounds like you're working in a different area to what you're posting your question on.

Agustee 29-Jun-12 5:20am

sry i have changed my code later, if file exist i used xmldocument to load my xml file then i used xpath. i'm new to xml tats y this problem.

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Elangovan.N · Accepted Answer · 2012-06-27T23:41:00

First a fall, you have a mistake in xml formation.
The output of your xml looks like this.

XML

<messages>
    <date>strDate</date>
    <time>strTime</time>
    <subject>strSubject</subject>
    <ajanta>strAjanta</ajanta>
</messages>

Here xml will consider

XML

<message></message>

as the parent node and if u inserted one more record, the same parent node is again created,so xml cannot create.

For this you need to have one parent and inside that sub- parent, your xml formation should be like this,

XML

<all-message>
<messages id="0">
    <date>strDate</date>
    <time>strTime</time>
    <subject>strSubject</subject>
    <ajanta>strAjanta</ajanta>
</messages>
<messages id="1">
    <date>strDate1</date>
    <time>strTime1</time>
    <subject>strSubject1</subject>
    <ajanta>strAjanta1</ajanta>
</messages>
</all-message>

if you have your own unique id for

XML

<message></message>

it will be useful,incase you printing only that required <message>.

Hope this link will help for your question:
http://msdn.microsoft.com/en-us/library/5x8bxy86(v=vs.80).aspx[^]