Reading a XML File, what am I doing wrong?

nuno.silva · 2017-04-04

Hi,
I need to call a web service and read the XML.
I can call the web service, receive the reply but when I try to read the values, for example put the values on a message, I always get the error “A DotNet variable has not been instantiated. Attempting to call System.Xml.XmlNode.Value in CodeUnit CallWS: GetUsers”

Any sugestion?
thanks in advance,
NS

ftornero · 2017-04-05

You need to change all reference from XMLNodexx.Value to XMLNodexx.InnerText

And you need to remove the namespaces too.

You can use something like that

RemoveNamespace(XMLDocIn : DotNet "System.Xml.XmlDocument";VAR XMLDocOut : DotNet "System.Xml.XmlDocument")
// before this function your tag looks like this: <namespace:tagname>sample text</tagname>
// after this function your tag looks like this: <tagname>sample text</tagname>
// additionally all namespace references in the head are removed.
XslTransform :=  XslTransform.XslTransform;
XMLStyleSheet := XMLStyleSheet.XmlDocument;
XMLStyleSheet.InnerXml(
'<?xml version="1.0" encoding="UTF-8"?>' +
'<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">' +
'<xsl:output method="xml" encoding="UTF-8" />' +
'<xsl:template match="/">' +
'<xsl:copy>' +
'<xsl:apply-templates />' +
'</xsl:copy>' +
'</xsl:template>' +
'<xsl:template match="*">' +
'<xsl:element name="{local-name()}">' +
'<xsl:apply-templates select="@* | node()" />' +
'</xsl:element>' +
'</xsl:template>' +
'<xsl:template match="@*">' +
'<xsl:attribute name="{local-name()}"><xsl:value-of select="."/></xsl:attribute>' +
'</xsl:template>' +
'<xsl:template match="text() | processing-instruction() | comment()">' +
'<xsl:copy />' +
'</xsl:template>' +
'</xsl:stylesheet>'
);

XslTransform.Load(XMLStyleSheet);
writer := writer.StringWriter();
XslTransform.Transform(XMLDocIn, nullXsltArgumentList, writer);
XMLDocOut := XMLDocOut.XmlDocument;  // Inicializa el XML de salida
XMLDocOut.InnerXml(writer.ToString());

Local vars

Name DataType Subtype Length
XMLStyleSheet DotNet System.Xml.XmlDocument.'System.Xml, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089'
XslTransform DotNet System.Xml.Xsl.XslTransform.'System.Xml, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089'
writer DotNet System.IO.StringWriter.'mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089'
nullXsltArgumentList DotNet System.Xml.Xsl.XsltArgumentList.'System.Xml, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089'

And put this code:

RemoveNamespace(XMLResponseDoc, XMLResponseDoc);

before this line:

XMLNodeList := XMLResponseDoc.GetElementsByTagName('Utilizador');

ftornero · 2017-04-05

Sorry another thing to do is delete the /text() part in SelectSingleNode:

XMLNodeID := XMLNodeContainer.SelectSingleNode('Id');
XMLNodeUserName := XMLNodeContainer.SelectSingleNode('Username');
XMLNodeFullName := XMLNodeContainer.SelectSingleNode('FullName');

HannesHolst · 2017-04-05

At which line does the debugger stop?

nuno.silva · 2017-04-05

at the message line

HannesHolst · 2017-04-05

Maybe this works?

XMLNodeList := XMLResponseDoc.GetElementsByTagName('Utilizador');
FOR I := 0 TO XMLNodeList.Count - 1 DO BEGIN
XMLNodeContainer := XMLNodeList.Item(I);
XMLNodeID := XMLNodeContainer.SelectSingleNode('Id/text()');
XMLNodeUserName := XMLNodeContainer.SelectSingleNode('Username/text()');
XMLNodeFullName := XMLNodeContainer.SelectSingleNode('FullName/text()');

MESSAGE('%1 - %2 - %3', FORMAT(XMLNodeID.Value), FORMAT(XMLNodeUserName.Value), FORMAT(XMLNodeFullName.Value));
END;

nuno.silva · 2017-04-05

The XMLNodeContainer is the type of System.Xml.XmlNode, correct?
I get the same error.
If I put the code below, ir runs through the records returned by the web service

IF NOT ISNULL(XMLNodeID) THEN
MESSAGE('%1 - %2 - %3', FORMAT(XMLNodeID.Value), FORMAT(XMLNodeUserName.Value), FORMAT(XMLNodeFullName.Value));

ftornero · 2017-04-05

You need to change all reference from XMLNodexx.Value to XMLNodexx.InnerText

And you need to remove the namespaces too.

You can use something like that

RemoveNamespace(XMLDocIn : DotNet "System.Xml.XmlDocument";VAR XMLDocOut : DotNet "System.Xml.XmlDocument")
// before this function your tag looks like this: <namespace:tagname>sample text</tagname>
// after this function your tag looks like this: <tagname>sample text</tagname>
// additionally all namespace references in the head are removed.
XslTransform :=  XslTransform.XslTransform;
XMLStyleSheet := XMLStyleSheet.XmlDocument;
XMLStyleSheet.InnerXml(
'<?xml version="1.0" encoding="UTF-8"?>' +
'<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">' +
'<xsl:output method="xml" encoding="UTF-8" />' +
'<xsl:template match="/">' +
'<xsl:copy>' +
'<xsl:apply-templates />' +
'</xsl:copy>' +
'</xsl:template>' +
'<xsl:template match="*">' +
'<xsl:element name="{local-name()}">' +
'<xsl:apply-templates select="@* | node()" />' +
'</xsl:element>' +
'</xsl:template>' +
'<xsl:template match="@*">' +
'<xsl:attribute name="{local-name()}"><xsl:value-of select="."/></xsl:attribute>' +
'</xsl:template>' +
'<xsl:template match="text() | processing-instruction() | comment()">' +
'<xsl:copy />' +
'</xsl:template>' +
'</xsl:stylesheet>'
);

XslTransform.Load(XMLStyleSheet);
writer := writer.StringWriter();
XslTransform.Transform(XMLDocIn, nullXsltArgumentList, writer);
XMLDocOut := XMLDocOut.XmlDocument;  // Inicializa el XML de salida
XMLDocOut.InnerXml(writer.ToString());

Local vars

Name DataType Subtype Length
XMLStyleSheet DotNet System.Xml.XmlDocument.'System.Xml, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089'
XslTransform DotNet System.Xml.Xsl.XslTransform.'System.Xml, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089'
writer DotNet System.IO.StringWriter.'mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089'
nullXsltArgumentList DotNet System.Xml.Xsl.XsltArgumentList.'System.Xml, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089'

And put this code:

RemoveNamespace(XMLResponseDoc, XMLResponseDoc);

before this line:

XMLNodeList := XMLResponseDoc.GetElementsByTagName('Utilizador');

ftornero · 2017-04-05

Sorry another thing to do is delete the /text() part in SelectSingleNode:

XMLNodeID := XMLNodeContainer.SelectSingleNode('Id');
XMLNodeUserName := XMLNodeContainer.SelectSingleNode('Username');
XMLNodeFullName := XMLNodeContainer.SelectSingleNode('FullName');

nuno.silva · 2017-04-06

I already founded a solution below, but I think yours is best, so I replaced my solution by yours.

Thanks @ftornero

  XMLNodeListRead := XMLResponseDoc.GetElementsByTagName('Id');
  XMLNodeID := XMLNodeListRead.Item(I);
  
  XMLNodeListRead := XMLResponseDoc.GetElementsByTagName('Username');
  XMLNodeUserName := XMLNodeListRead.Item(I);
  
  XMLNodeListRead := XMLResponseDoc.GetElementsByTagName('FullName');
  XMLNodeFullName := XMLNodeListRead.Item(I);

Reading a XML File, what am I doing wrong?

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