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Subject:
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Looping through attributes in an XML document
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Posted By:
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francislang
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Post Date:
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11/16/2004 8:47:52 AM
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I'm trying to find a neat way of looping through an XML document so that I can get the attributes and the relevant values so that I can save them.
The only way i've managed to do this so far is nesting loops inside each other. One loop for each level. This seems a bit restrictive though. What if another level were to appear in the document?
Here's my code:
For Each Node In myNodeList
If Node.HasChildNodes Then
For Each childNode In Node
logIt.dBug(childNode.Name)
For Each Attribute In childNode.Attributes
saveAttribute(Attribute.Name, Attribute.Value)
Next
If childNode.HasChildNodes Then
For Each nextChildNode In childNode
logIt.dBug(nextChildNode.Name)
For Each Attribute In nextChildNode.Attributes
saveAttribute(Attribute.Name, Attribute.Value)
Next
Next
End If
Next
End If
Next
Any ideas would be greatly appreciated.
Many thanks,
Francis
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Reply By:
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joefawcett
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Reply Date:
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11/16/2004 9:03:03 AM
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Sounds like you need recursion.
Pseudo code:
function saveAttribute(Name, Value)
function saveAttributes(Node)
{
loop through attributes and call saveAttribute for each one
if Node has children loop through children and call saveAttributes passing in each node
}
function main()
{
get document element and call saveAttributes(documentElement)
}
main()
--
Joe (Microsoft MVP - XML)
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Reply By:
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mhkay
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Reply Date:
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11/16/2004 9:12:00 AM
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The classic way to walk a tree is with a recursive function. In pseudocode:
function processElement(Element e) {
doSomethingWith(e);
for each child c of e {
processElement(c)
}
}
Michael Kay
http://www.saxonica.com/
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Reply By:
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francislang
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Reply Date:
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11/17/2004 8:57:07 AM
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Thanks for your comments.
I have attempted a structure similar to your advice, but I am receiving a peculiar outcome.
I have a loop that goes through a nodlist:
For Each node In NodeList
saveNodeAttributes(node)
Next node
Then setup the other function for the recursion:
Public Sub saveNodeAttributes(ByVal Node As Xml.XmlNode)
Dim attribute As Xml.XmlAttribute
If Not Node.Attributes Is Nothing Then
For Each attribute In Node.Attributes
logIt.dBug(attribute.Name)
Next attribute
End If
If Node.HasChildNodes Then
saveNodeAttributes(Node.FirstChild)
ElseIf Not Node.NextSibling Is Nothing Then
saveNodeAttributes(Node.NextSibling)
ElseIf Not Node.ParentNode.NextSibling Is Nothing Then
saveNodeAttributes(Node.ParentNode.NextSibling)
End If
End Sub
It checks to see if the node has any "children", if it does then select the "firstchild". If not check if there are any "siblings", if not then go back to the "parent" and choose the next sibling.
This however is outputting the 2nd half of the document's attributes twice?
Any idea what could be wrong?
Thanks,
Francis
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Reply By:
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joefawcett
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Reply Date:
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11/17/2004 10:02:39 AM
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You don't need to worry about siblings and parents.
--
Joe (Microsoft MVP - XML)
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