asked on

Using XPath to test if XML node exists

Using ASP, I'm trying to access specific XML nodes with .SelectSingleNode("//TAGNAME") and test if the tag exists. Accessing the nodes (when they exist) is no problem, but the test for existance has me stumped.
I tried:
set thisNode = xmlDoc.documentElement.SelectSingleNode("//TAGNAME")
      If StrComp("thisNode.Text", "" )<> 0 Then
            Response.Write thisNode.Text
      End If
but it gives me an 'object required' error

Should I use getElementsByTagName() instead?

I'm sure this is not a very difficult question for you experts, but I'm stuck on this and a quick solution is very important, so I'm assigning more points.
Thanks

davidlars99

do not use "set" (and maybe """ around thisNode.Text)

davidlars99

and make sure you have

> Dim xmlDoc As New XML.XMLDocument

before you do anything

davidlars99

or
> Set xmlDoc=Server.CreateObject("microsoft.xmldom")

davidlars99

if none of these help try

> thisNode = xmlDoc.documentElement.SelectSingleNode("//TAGNAME").Text

that's all I could think of.. :)

Ezog

ASKER

I have:
set xmlDocL = CreateObject("Microsoft.XMLDom")
xmlDoc.async = False
Set xmlDoc = objXMLHTTP.responseXML

If I use
thisNode = xmlDoc.documentElement.SelectSingleNode("//TAGNAME").Text

I still get the 'object reqiured' error

Ezog

ASKER

when I tried:

set objElements = xmlDoc.getElementsByTagName("TAGNAME")
If objElements.Item(0) Is Nothing Then
thisNode = ""
Else
thisNode = objElements.Item(0).nodeTypeString
End If
Response.Write thisNode

I get 'element' as response instead of the string value

davidlars99

what line is that you getting error on..?

davidlars99

> set xmlDocL = CreateObject("Microsoft.XMLDom")
what's xmlDoc-"L " shouldn't it be xmlDoc

Ezog

ASKER

the "L" - just a typo,

I get the error on the Response.Write line

Ezog

ASKER

I also tried:

set thisNode = xmlDoc.documentElement.SelectSingleNode("//TAGNAME")
If len (thisNode.Text) >0 Then
Response.Write thisNode.Text
End If

I get an error only when the tag does not exist.

davidlars99

try
> Set xmlDoc = CreateObject("Msxml2.DOMDocument")

and something very important

> Set xmlDoc = objXMLHTTP.responseXML
after this xmlDoc is not an object anymore...

I think that correct way would be following...

Set xmlDoc = CreateObject("Msxml2.DOMDocument")
xmlDoc.load(path_to_the_same_file_which_is_loaded_into_objXMLHTTP)

set thisNode = xmlDoc.documentElement.SelectSingleNode("//TAGNAME")
If len (thisNode.Text) >0 Then
Response.Write thisNode.Text
End If

davidlars99

when you try "thisNode.Text" it's looking for the object, but with "Set xmlDoc = objXMLHTTP.responseXML" "xmlDoc" would never be the object

Ezog

ASKER

I inserted
Set xmlDoc = CreateObject("Msxml2.DOMDocument")
and replaced
Set xmlDoc = objXMLHTTP.responseXML
with
xmlDoc.load("http://URL")
path_to_the_same_file_which_is_loaded_into_objXMLHTTP

but get:
Microsoft VBScript runtime error '800a01a8'
Object required
/response.asp, line 49
which is:
set thisNode = xmlDoc.documentElement.SelectSingleNode("//TAGNAME")

Also, I only received an error if the tag is missing. If the tag exists, I can enter its value into the form with the following:
Set rootNode = xmlDoc.documentElement
Set thisNode = rootNode.SelectSingleNode("//TAGNAME")
Response.Write thisNode.Text

davidlars99

how about

Set xmlDoc = CreateObject("Msxml2.DOMDocument")
xmlDoc.load(path_to_the_same_file_which_is_loaded_into_objXMLHTTP)
set xmlResponse=xmlDoc.responseXML 'also try without "set"

thisNode = xmlResponse.documentElement.SelectSingleNode("//TAGNAME")
If len (thisNode.Text) >0 Then
Response.Write thisNode.Text
End If

davidlars99

ok, ignore my last post and try this first

Set xmlDoc = CreateObject("Msxml2.DOMDocument")
xmlDoc.load(path_to_the_same_file_which_is_loaded_into_objXMLHTTP)

thisNode = xmlDoc.documentElement.SelectSingleNode("//TAGNAME")
If len (thisNode.Text) >0 Then
Response.Write thisNode.Text
End If

is loading file XML or some other type..?

Ezog

ASKER

I get with and without "set":
'Microsoft VBScript runtime error '800a01b6'
Object doesn't support this property or method: 'responseXML'
/response.asp, line 27

davidlars99

did you try one above your post..?

Ezog

ASKER

I'm getting a feed with about 30 possible tags but only about half of them are returned at any given time. I don't want to use stylesheets so I try to find the missing tags with conditionals...
maybe I'm going about it the wrong way

Ezog

ASKER

hm, I don't understand that comment. What do you mean with "above your post"?

davidlars99

I mean this one

Set xmlDoc = CreateObject("Msxml2.DOMDocument")
xmlDoc.load(path_to_the_same_file_which_is_loaded_into_objXMLHTTP)

thisNode = xmlDoc.documentElement.SelectSingleNode("//TAGNAME")
If len (thisNode.Text) >0 Then
Response.Write thisNode.Text
End If

Ezog

ASKER

I think I might have figured it out:
This one works with the old
Set xmlDoc = objXMLHTTP.responseXML

set objElements = objXML.selectSingleNode("//ZONING")
if objElements is nothing then
Response.Write "(Not available)"
else
Response.Write objElements.Text
end if

ASKER CERTIFIED SOLUTION

davidlars99

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Ezog

ASKER

actualy, I rewrote the thing and used objXML instead of xmlDOC (just for reference or the code would not make sence!)

Ezog

ASKER

I think it works... at least so far, but I would like to leave the treat open until I have done some more testing. Thank you so much for you help! I will award your points on closing.

gnudiff

> Using XPath to test if XML node exists

Is there any reason for not using simply SelectSingleNode("count(//TAGNAME)") Xpath? It should return the count of TAGNAME nodes, 0 - if no such nodes exist...

Ezog

ASKER

I tried the SelectSingleNode("count(//TAGNAME)") and got the following error:

msxml3.dll error '80004005'
Unknown method. -->count(//<--STATE)