Question

So I have this pretty large XML file (40MB) that I’ll have to repeatedly search. I’ve been schooled on the benefits of DOMDocument usage with XPath, and I thought I had it right, but I’m getting the Obj Var Not Set nonsense.

Here’s the initial load…I think its loading because it delays an appropriate length of time for a 40mb file & returns no error.

Dim someElement As IXMLDOMNode
Dim xmlDoc As Object
Set xmlDoc = CreateObject("Msxml2.DOMDocument.6.0")

'<-thats a valid file name lookup
xmlDoc.Load DLookup("gsgtver", "Eramdat", "EramID = 1") 

So heres where it gets dicey. I need a IXMLDOMNode to read the parced xmlDoc object. I checked the MsXml 6.0 reference library, and I’m getting the var type when I dim (you know, the list of types that fill in for us noobs).
And after I have a IXMLDOMNode set I get the list of methods (like “.text”) when I try to assign, but I’m bangin on this error ….. could be a bum xpath string (although I pretty much verbatim stole it from the xpath tutorial).

sNodeName = "/Fix_Records/FixRecord/FixID[1]/Latitude"
Set someElement = xmlDoc.SelectSingleNode(sNodeName)

'yes, I dimmed xBuffer as a string up above
sBuffer = someElement.text 

Incedently, I REALLY wanna do a “FixID = ‘mystring’ ” sorta thing, but I’m doing element 1 just to get it workin.
And here’s the top of the xml file:

<Fix_Records xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
             xsi:noNamespaceSchemaLocation="Fix.xsd"> 
 <!-- ******************************************************** -->
 <!-- Local SITE ID        : ZAB                               -->
 <!-- Local Release Version: a082a210                          -->
 <!-- NASD/NADR Version    : z084b210                          -->
 <!-- Date                 : 02-03-2011 19:02:56               -->
 <!-- ******************************************************** -->

    <FixRecord>
      <FixId>00BTR</FixId>
      <IcaoCode>K7</IcaoCode>
      <FixType>WAYPOINT</FixType>
      <FixName>BTR055100</FixName>
      <FixinUs>true</FixinUs>
      <IsNational>true</IsNational>
      <HighPowerVor>false</HighPowerVor>
      <DPositionMapData>false</DPositionMapData>
      <Latitude>31170205N</Latitude>
      <Longitude>089353453W</Longitude>
      <AngularCorr>-0.010472</AngularCorr>
      <XSpherical>0.006082693951808</XSpherical>
      <YSpherical>-0.85612436871425</YSpherical>
      <ZSpherical>0.516734038096893</ZSpherical>
    </FixRecord>
    <FixRecord>
      <FixId>00N10</FixId>
      <IcaoCode>MM</IcaoCode>

Thank you…..you smart people rock.

Answer 1

You have a case sensitive problem – you’re looking for FixID, you’ve actually got FixId.
When you try and access its text you throw an exception as you have no actual object.

EDIT: as pointed out by Jean-François Corbett, your XPath is also wrong. Here is an updated Xpath solving both problems:

"/Fix_Records/FixRecord[FixId='Id you want']/Latitude"

You may also want to test if you’ve got a node to access, see the answer below for some tips.