Update. 

Again through trial and error I was able to determine that this "wrapper" in 
the xsl seems to be  the culprit.

		public bool MerchandisedProduct(string connectionString, XPathNavigator nav)
		{
		SqlFunctions mySqlFunctions = new SqlFunctions(connectionString, nav);
		return mySqlFunctions.MerchandisedProduct();
		}

It seems that if I use this wrapper with an XPathNavigator that points to 
more than one node it fails. The reason that I know that it is the wrapper in 
the XSL and not my function is that I changed the return so that it always 
returned 'false' so the call was not made to my custom code.

Any idea on how I can change the wrapper so that it handles multiple nodes 
as return by an XPath statement like:

bsi:MerchandisedProduct($CatalogConnectionString,Relationship/Relation/SKU)

?

Thank you.

Kevin

"Kevin Burton" wrote:

> Through trial and error I think I have narrowed down the problem to the 
> following:
> 
> Not Merchandised Errors - <xsl:value-of 
> select="count(/Envelope/Message[(MessageID = $MessageTestList/root/list/item) 
> and 
> (bsi:MerchandisedProduct($CatalogConnectionString,Relationship/Relation/SKU))])"/>
> 
> May assumption is that
> 
> Relationship/Relation/SKU
> 
> in the context about is passed to my custom XSL function as a single node. 
> Perhaps that assumption is in error. So now this is a query question. The 
> format of the XML document looks like:
> 
> <Envelope>
>   <Message>
>     <MessageId>1234</MessageId>
>     <Relationship>
>          <Relation>
>              <SKU>5678</SKU>
>          </Relation>
>     </Relationship>
>   </Message>
> </Envelope>
> 
> I want to make sure that the MessageID is in the first list (that is an 
> XPath expression). Now I want to make sure that each SKU that is a sub set of 
> the nodes that match the first XPath to be passed to the custom function. 
> 
> Is that confusing enough?
> 
> Kevin
> "Kevin Burton" wrote:
> 
> > I have a transform that works on a large number of files. Every once and a 
> > while I get the following exception thrown:
> > 
> > A first chance exception of type 'System.Xml.Xsl.XslTransformException' 
> > occurred in System.Data.SqlXml.dll
> > System.Xml.Xsl.XslTransformException: Cannot convert a node-set which 
> > contains zero nodes or more than one node to a single node.
> >    at System.Xml.Xsl.Runtime.XsltConvert.ToNode(IList`1 listItems)
> >    at <xsl:template match="/">(XmlQueryRuntime 
> > {urn:schemas-microsoft-com:xslt-debug}runtime, XPathNavigator 
> > {urn:schemas-microsoft-com:xslt-debug}current)
> >    at Root(XmlQueryRuntime {urn:schemas-microsoft-com:xslt-debug}runtime)
> >    at Execute(XmlQueryRuntime {urn:schemas-microsoft-com:xslt-debug}runtime)
> >    at System.Xml.Xsl.XmlILCommand.Execute(Object defaultDocument, 
> > XmlResolver dataSources, XsltArgumentList argumentList, XmlSequenceWriter 
> > results)
> >    at System.Xml.Xsl.XmlILCommand.Execute(Object defaultDocument, 
> > XmlResolver dataSources, XsltArgumentList argumentList, XmlWriter writer, 
> > Boolean closeWriter)
> >    at System.Xml.Xsl.XmlILCommand.Execute(IXPathNavigable contextDocument, 
> > XmlResolver dataSources, XsltArgumentList argumentList, XmlWriter results)
> >    at System.Xml.Xsl.XmlILCommand.Execute(IXPathNavigable contextDocument, 
> > XmlResolver dataSources, XsltArgumentList argumentList, Stream results)
> >    at System.Xml.Xsl.XslCompiledTransform.Transform(IXPathNavigable input, 
> > XsltArgumentList arguments, Stream results)
> > 
> > 
> > Any hints on how I might be able to isolate the input that is causing the 
> > problem and maybe the line(s) in the stylesheet that are involved?
> > 
> > Thank you.
> > 
> > Kevin
> >