Retrieving data from xml using xmlDocument, xmlNode and xmlNodelist - vb.net

Question

This is a sample code in vb.net in which i retrieve the details of elements without attributes.
For Each standardItemInfoNode In ItemInfoNodes
baseDataNodes = ItemInfoNodes.ChildNodes
bFirstInRow = True
For Each baseDataNode As XmlNode In baseDataNodes
If (bFirstInRow) Then
bFirstInRow = False
Else
Response.Write("<br>")
End If
Response.Write(baseDataNode.Name & ": " & baseDataNode.InnerText)
Next
Next
How can i retrieve the details of the xml like having node with attributes and its child also having attributes. I need to retrieve all the attributes of node and its child node which are present in the middle of other xml tags.

Answer 1

I'm not sure exactly what you're asking, and I can't give you a specific example without knowing the format of the XML you are trying to process, but I think what you are looking for is the Attributes property of the XmlNode objects. Each XmlNode has an Attributes property that allows you to access all the attributes for that node. Here's the MSDN page that explains it (and provides a simple example):
http://msdn.microsoft.com/en-us/library/7f285y48.aspx
EDIT:
Using the example XML you posted in the comment, you could read the all the values and attributes like this:
Dim doc As XmlDocument = New XmlDocument()
doc.LoadXml("<EventTracker><StandardItem><Header1>Header1 Text</Header1> <Header2>Header2 Text</Header2></StandardItem><Item> <Events> <EventSub EventId='73' EventName='Orchestra' Description='0'> <Person PersonId='189323156' PersonName='Chandra' Address='Arunachal'/><Person PersonId='189323172' PersonName='Sekhar' Address='Himachal'/></EventSub> </Events> </Item> </EventTracker>")
Dim header1 As String = doc.SelectSingleNode("EventTracker/StandardItem/Header1").InnerText
Dim header2 As String = doc.SelectSingleNode("EventTracker/StandardItem/Header2").InnerText
For Each eventSubNode As XmlNode In doc.SelectNodes("EventTracker/Item/Events/EventSub")
Dim eventId As String = eventSubNode.Attributes("EventId").InnerText
Dim eventName As String = eventSubNode.Attributes("EventName").InnerText
Dim eventDescription As String = eventSubNode.Attributes("Description").InnerText
For Each personNode As XmlNode In eventSubNode.SelectNodes("Person")
Dim personId As String = personNode.Attributes("PersonId").InnerText
Dim personName As String = personNode.Attributes("PersonName").InnerText
Dim personAddress As String = personNode.Attributes("Address").InnerText
Next
Next
However, if you are loading all the data in the XML like this, I would recommend deserializing the XML into an EventTracker object. Or, as I said in my comment on your post, if the only purpose for reading the XML document is to transform it into another XML or HTML document, I would recommend using XSLT, instead.
If you want to test if an attribute exists, you can do something like this:
Dim attribute As XmlNode = personNode.Attributes.GetNamedItem("PersonId")
If attribute IsNot Nothing Then
Dim personId As String = attribute.InnerText
End If
However, this would be much easier with serialization since the deserialized object would simply have null properties for any elements that didn't exist.

Answer 2

You can use SelectSingleNode("XPath or NodeName") and loop through the Attributes.Item(index) on that node. You can also, if you know the childnode name in advance, loop through SelectSingleNode("XPath Or NodeName").SelectSingleNode("XPath or ChildName").Attributes.Item(index).