how can i insert a complete node to an xml in vb.net?

Question

i have the following function which brings a nodelist and i need to add it to the following xml

 Public Function Salida(ByVal est As String, ByVal err As String, Optional node As Object = Nothing) As String
    Dim m_xmld = New XmlDocument
    Try
        m_xmld.LoadXml("<tx><estado></estado><info></info></tx>")
        m_xmld.SelectSingleNode("tx/estado").InnerText = est
        m_xmld.SelectSingleNode("tx/info").InnerText = err

        If Not node Is Nothing Then

            m_xmld.AppendChild(node)

        End If

    Catch ex As Exception
        m_xmld.InnerText = "Error"


    End Try
    Return m_xmld.InnerXml

End Function

but when I try to add it, I get the following error "{"Unable to convert an object of type 'System.Xml.XmlElementList' to type 'System.Xml.XmlNode'."}"

how to name the function and obtain the node:

mvarXmlSalida = Util.Salida("0", "", xmldoc.GetElementsByTagName("file"))



 <Transport>
     <file>
        <name>test.txt</name>
        <size>1,52 Kb</size>
        <type>.txt</type>
        <data>test data</data>
        <option>ExactName</option>
      </file>
    <Transport>

It is better to use **LINQ to XML**, and pass XML parameter as `XElement` data type. — Yitzhak Khabinsky, Dec 27 '22 at 20:33
What line are you getting the error on? What does the Transport element have to do with the tx element? NOT CLEAR AT ALL! — dbasnett, Dec 28 '22 at 14:09

score 0 · Answer 1 · answered Dec 28 '22 at 07:36

It's not quite clear what you're trying to append, but the following should be helpful:

Add the following Imports

Imports System.IO
Imports System.Xml.Linq

Public Function Salida(est As String, err As String, Optional node As XElement = Nothing) As String
    Dim xmlStr As String = "<tx><estado></estado><info></info></tx>"

    'parse XML
    Dim root As XElement = XElement.Parse(xmlStr)

    If node IsNot Nothing Then
        root.Elements("estado").FirstOrDefault().AddAfterSelf(node) 'option 1
        'root.Elements("info").FirstOrDefault().AddAfterSelf(node) 'option 2

        'root.Elements("estado").FirstOrDefault().AddFirst(node) 'option 3
        'root.Elements("info").FirstOrDefault().AddFirst(node) 'option 4
    End If

    'save XML to string
    Using tr As StringWriter = New StringWriter
        root.Save(tr)
        Return tr.ToString
    End Using
End Function

Usage 1:

Dim xmlInput As String = "
     <Transport>
         <file>
             <name>test.txt</name>
             <size>1,52 Kb</size>
             <type>.txt</type>
             <data>test data</data>
             <option>ExactName</option>
         </file>
     </Transport>"

Dim nodeTransport As XElement = XElement.Parse(xmlInput)

'node: Transport
Dim result As String = Salida("0", "", nodeTransport)

Debug.WriteLine(result)

Usage 2:

Dim xmlInput As String = "
     <Transport>
         <file>
             <name>test.txt</name>
             <size>1,52 Kb</size>
             <type>.txt</type>
             <data>test data</data>
             <option>ExactName</option>
         </file>
     </Transport>"

Dim nodeTransport As XElement = XElement.Parse(xmlInput)
Dim nodeFile As XElement = nodeTransport.Elements("file").FirstOrDefault()

'node: file
Dim result As String = Salida("0", "", nodeFile)

Debug.WriteLine(result)

Result (Usage 2):

<?xml version="1.0" encoding="utf-16"?>
<tx>
  <estado></estado>
  <file>
    <name>test.txt</name>
    <size>1,52 Kb</size>
    <type>.txt</type>
    <data>test data</data>
    <option>ExactName</option>
  </file>
  <info></info>
</tx>

Resources:

score -1 · Accepted Answer · answered Dec 28 '22 at 14:43

A guess,

First your function re-written.

Public Function Salida(ByVal est As String,
                        ByVal err As String,
                        Optional node As XElement = Nothing) As XElement

    Dim m_xmld As XElement
    m_xmld = <tx><estado><%= est %></estado><info><%= err %></info></tx>
    If Not node Is Nothing Then
        m_xmld.Add(node)
    End If

    Return m_xmld
End Function

Second, showing it in use.

Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
    Dim xe As XElement
    xe = <Transport>
             <file>
                 <name>test.txt</name>
                 <size>1,52 Kb</size>
                 <type>.txt</type>
                 <data>test data</data>
                 <option>ExactName</option>
             </file>
         </Transport>

    Dim result As XElement
    result = Salida("EST", "ERR", xe.<file>.FirstOrDefault)

    'result
    '<tx>
    '  <estado>EST</estado>
    '  <info>ERR</info>
    '  <file>
    '    <name>test.txt</name>
    '    <size>1,52 Kb</size>
    '    <type>.txt</type>
    '    <data>test data</data>
    '    <option>ExactName</option>
    '  </file>
    '</tx>
End Sub

As I mentioned in my comment, what you are trying to do is NOT CLEAR!

how can i insert a complete node to an xml in vb.net?

2 Answers2