updating XML Child

Question

User-379502100 posted

I'm hoping that someone can point me in the right direction.

I have been searching for a way to update a value in a child node but have been unable to find a way that fits the format of the XML file.

In the example below, I need to update the value in childnode(8) from value="341000" to what has been selected from a comboBox "cbTxFreq.Text".

The best I have been able to do is to append data to the childnode.

Is there a method to simply update the Value and save it?

I'm using VB.Net 2008

Thanx in advance

 

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XML SAMPLE

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>

<configuration>

<digital type="bool" value="false" />

<dl_map_timer type="int" value="50" />

<pilot_fix type="bool" value="true" />

<adpt_mod type="bool" value="true" />

<broadcast_modulation type="string" value="bpsk_12" />

<cell_radius type="float" value="50" />

<chnl_bw type="float" value="3.5" />

<cyc_prfx type="float" value="0.25" />

<dl_cf type="int" value="3410000" />

</configuration>

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Dim MyXML As New XmlDocument()

Dim filename As String = "c:\ObrXMLFile.xml"

MyXML.Load(filename)

Dim MyXMLNode As XmlNode = MyXML.SelectSingleNode("/configuration")

If MyXMLNode IsNot Nothing Then

MyXMLNode.ChildNodes(8).InnerText ="dl_cf=" & "int" & " value=" & cbTxFreq.Text

End If
' Save the Xml.

MyXML.Save("c:\ObrXMLFile.xml")

Answer 1

User-1806150748 posted

I have tried this and it is working.

  Dim MyXML As New XmlDocument()

        Dim filename As String = "C:\ObrXMLFile.xml"

        MyXML.Load(filename)

        Dim MyXMLNode As XmlNode = MyXML.SelectSingleNode("/configuration/dl_cf")

        If MyXMLNode IsNot Nothing Then
            MyXMLNode.Attributes("value").Value = cbTxFreq.Text
            ' MyXMLNode.ChildNodes(8).InnerText = "dl_cf=" & "int" & " value=" & "newval"

        End If
        ' Save the Xml.

        MyXML.Save("C:\ObrXMLFile.xml")

Answer 2

User-379502100 posted

Works very nice indeed. Thanx

Could you sugest how to use this form to update multipul ChildNodes that fall under the "/configuration" as in the example.

 

       Dim MyXMLNode As XmlNode = MyXML.SelectSingleNode("/configuration")

        If MyXMLNode IsNot Nothing Then

              MyXMLNode.dl_cf.Attributes("value").Value = cbTxFreq.Text

              MyXMLNode.chnl_bw.Attributes("value").Value = cbBW.Text
      end if

or somthig like that.

Being new to XML I'm still having problems with proper formating.

 

 

Answer 3

User-1806150748 posted

yes, you have to select each of nodes like 

Dim MyXMLNode As XmlNode = MyXML.SelectSingleNode("/configuration/dl_cf")

and then update values using attribute.

If this helps, please mark this as answer.

Answer 4

User-379502100 posted

That help a great deal.

thanx again

Answer 5

User-1806150748 posted

Can you mark , my reply as answer, that will be great help!