[2005] Delete XML Nodes in a Loop

[OneSource]

Hi,

Given the following XML snippet

  <Parent>
    <Child LIID="1" />
    <Child LIID="2" />
    <Child LIID="3" />
    <Child LIID="4" />
    <Child LIID="5" />
  </Parent>

how do I loop through all of the child controls and delete them one by one? I tried using

For Each ndeChild As XmlNode in ndeParent.ChildNodes
      ndeParent.RemoveChild(ndeChild)
Next

but doing a "RemoveChild" while looping causes the For Each loop to exit on the very first child node. Any ideas?

Thanks!

[gep13]

Hey,

This is one way of doing it:

    Dim xmlDoc As New XmlDocument()

    Private Sub deleteXML_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        xmlDoc.Load("XMLFile2.xml")
    End Sub

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        For Each xmlNode As XmlNode In xmlDoc.ChildNodes
            xmlNode.RemoveAll()
        Next

        MessageBox.Show(xmlDoc.InnerXml.ToString())
    End Sub

This results in just the parent node being displayed. The RemoveAll Method of the XmlNode object removes everything.

Hope this helps!!!

Gary

[OneSource]

Thanks for the reply and the "RemoveAll" I'm sure would work, but I can't use it because the removal needs to be conditional. I made my example simple for the purpose of explanation, but I do need to remove the items one at a time based on the LIID.

Any other ideas anyone?

[gep13]

Hey,

I think you might be missing the point I was trying to make. RemoveAll works only on the instance of the XmlNode that it is currently looking at. It doesn't remove all the nodes.

I have modified the code slightly as follows:

    Dim xmlDoc As New XmlDocument()

    Private Sub deleteXML_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        xmlDoc.Load("XMLFile2.xml")
    End Sub

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        For Each node As XmlNode In xmlDoc.SelectNodes("/Parent/Child")
            If node.Attributes("LIID").Value = 1 Then
                node.RemoveAll()
            End If
        Next

        MessageBox.Show(xmlDoc.InnerXml.ToString())
    End Sub

This is now conditional on the LIID and the above results in the first child node only being removed.

Give it a try and let me know if this is what you want.

Gary

[OneSource]

I tried your technique and the result was that the "LIID" attribute was removed but not the node itself. In other words, the result would look like this:

  <Parent>
    <Child />
    <Child LIID="2" />
    <Child LIID="3" />
    <Child LIID="4" />
    <Child LIID="5" />
  </Parent>

This is consistent with the definition of "RemoveAll": "Removes all of the child nodes and/or attributes of the current node." I want the <Child /> node to go too, not just strip the "LIIID" attribute from it.

Thanks.

[gep13]

My bad, I haven't woke up properly this morning

Give this a try:

    Dim xmlDoc As New XmlDocument()

    Private Sub deleteXML_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        xmlDoc.Load("XMLFile2.xml")
    End Sub

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        For Each node As XmlNode In xmlDoc.SelectNodes("/Parent/Child")
            If node.Attributes("LIID").Value = 1 Then
                node.ParentNode.RemoveChild(node)
            End If
        Next

        MessageBox.Show(xmlDoc.InnerXml.ToString())
    End Sub

Hope that helps!!!

Gary

[OneSource]

gep13, "node.ParentNode.RemoveChild(node)" is essentially the same as "ndeParent.RemoveChild(ndeChild)", which is what I originally posted. Therefore, the issue is the same: "doing a "RemoveChild" while looping causes the For Each loop to exit on the very first child node.".

It looks like I'm going to have to think of a different way to do this.

[gep13]

The code that I posted doesn't break out of the loop, did you try it? The result in the MessageBox is:

  <Parent>
    <Child LIID="2" />
    <Child LIID="3" />
    <Child LIID="4" />
    <Child LIID="5" />
  </Parent>

I don't see why it would do anything else. I also tried the code above without the If Statement and the result was:

  <Parent>
  </Parent>

Gary

[OneSource]

Thanks for helping me figure this out. The issue was the way that I was creating the list of child nodes to be looped through. I was doing it this way:

Dim ndeParent As System.Xml.XmlNode = xmlDoc.SelectSingleNode("//Parent")

If Not ndeParent Is Nothing AndAlso ndeParent.ChildNodes.Count > 0 Then
	For Each ndeChild As System.Xml.XmlNode In ndeParent.ChildNodes
		ndeChild.ParentNode.RemoveChild(ndeChild)
	Next
End If

When I used your method for selecting nodes

For Each node As XmlNode In xmlDoc.SelectNodes("/Parent/Child")

it worked:

Thanks again for your help.

[gep13]

No probs!! Glad you got it sorted!!