How to handle and get values from dynamic tags from XML file in VBA macro - excel

Question

I have an XML file with 3 levels. Some of the tags are dynamic.(Please check below XML file)
I have to validate whether the tag "price" is present in all nodes or not and also need to get value of "price tag". I also need to fetch a value of every node present in XML file.
I tried validating whether every node in XML file is present or not but getting an error
VBA code snippet
Function fnReadXMLByTags2()
Dim mainWorkBook As Workbook
Set mainWorkBook = ActiveWorkbook
Dim obj As Object
Set obj = CreateObject("MSXML2.DOMDocument")
obj.async = False
XMLFileName = "C:\Prakash\Demo.xml"
obj.Load (XMLFileName)
Set authorNodes = obj.SelectNodes("//Books/book/author/text()")
Set titleNodes = obj.SelectNodes("//Books/book/title/text()")
Set genreNodes = obj.SelectNodes("//Books/book/genre/text()")
Set priceNodes = obj.SelectNodes("//Books/book/price/text()")
Set publish_dateNodes = obj.SelectNodes("//Books/book/publish_date/text()")
Set languageNodes = obj.SelectNodes("//Books/book/language/text()")
For i = 0 To (authorNodes.Length - 1)
If Not publish_dateNodes Is Nothing Then
Set publish_dateNodesValue = obj.SelectNodes("//Books/book/publish_date/text()")
publish_dateObj = publish_dateNodesValue(i).NodeValue
mainWorkBook.Sheets("Sheet3").Range("E" & i + 2).Value = publish_dateObj
Else
mainWorkBook.Sheets("Sheet3").Range("E" & i + 2).Value = "Blank"
End If
Next
End Function
Below error Message for line …
publish_dateObj = publish_dateNodesValue(i).NodeValue
Runtime error '91':
Object variable or With block variable not set
This is what I'm expecting in Excel file:
Excel sheet output
Below is the xml file :
<?xml version="1.0"?>
<Books>
<book id="1">
<author>ABC</author>
<title>Physics</title>
<genre>asd</genre>
<price>Rs.44</price>
<publish_date>20-10-2001</publish_date>
<description>Book1</description>
</book>
<book id="2">
<author>DEF</author>
<title>Chem</title>
<genre>XYZ</genre>
<publish_date>02-12-2016</publish_date>
<description>Book2</description>
</book>
<book id="3">
<author>GHI</author>
<title>Maths</title>
<genre>ABC</genre>
<price>Rs.500</price>
<language>English</language>
<description>Book3</description>
</book>
</Books>

Answer 1

It should be a procedure (Sub) not a function, because it does not return a value (make sure you know the difference).
The way you read the sub nodes made it impossible to keep the data consitent. You need to read all books first and then for each book the sub nodes:
Set CurrentNode = Books(iBook).SelectNodes("author/text()")(0)
The above reads reads the node author from book number iBook into CurrentNode and if it does not exist then CurrentNode will be Nothing. So you just need to check it and output the .NodeValue.
Note that I introduced an array NodesOutputList to be able to loop through the columns easily instead of repeating similar code over and over.
So you end up with something like:
Option Explicit
Public Sub fnReadXMLByTags2()
Dim mainWorkBook As Workbook
Set mainWorkBook = ThisWorkbook '<-- this is the workbook where this code is in ActiveWorkbook is the worbkook that has focus (is on top)
Dim wsOutput As Worksheet 'define output sheet
Set wsOutput = mainWorkBook.Worksheets("Sheet3")
Dim XMLFileName As String
XMLFileName = "D:\code\Demo.xml"
Dim obj As Object
Set obj = CreateObject("MSXML2.DOMDocument")
obj.async = False
obj.Load XMLFileName '<-- no parenthesis here!!!
Dim Books As Object 'get all books
Set Books = obj.SelectNodes("//Books/book")
Dim NodesOutputList() As Variant 'order in which the nodes are checked and output
NodesOutputList = Array("author/text()", "title/text()", "genre/text()", "price/text()", "publish_date/text()", "language/text()", "description/text()")
Dim iBook As Long
For iBook = 0 To Books.Length - 1 'loop through books
Dim iNode As Long
For iNode = LBound(NodesOutputList) To UBound(NodesOutputList) 'loop through nodes in the list
Dim CurrentNode As Object
Set CurrentNode = Books(iBook).SelectNodes(NodesOutputList(iNode))(0)
If Not CurrentNode Is Nothing Then
wsOutput.Cells(iBook + 2, iNode + 1).Value = CurrentNode.NodeValue
Else
wsOutput.Cells(iBook + 2, iNode + 1).Value = "blank"
End If
Next iNode
Next iBook
End Sub