Styjun

I have an XML document I try to extract values from using Delphi, and XMLDoc. Most parts work without problem. I use IXMLNode to select the node text. But I have one section which may contain CDATA. This always throws an exception when I try to get it.

My XML (relevant part) is similar to this

 <a>valuea</a>
 <b>My b value</b>
 <c>![CDATA[My cdata text goes here
It may have linefeed inside
like this
and I need to get all lines WITH linefeeds
]]>
</c>

My code today is something like this:

 var
 IDoc: IXMLDocument;
 INode: IXMLNode;
 XPathText : string;
 i : integer;

 // From a post in Embarcadero's Delphi XML forum.
 function selectNode(xnRoot: IXmlNode; const nodePath: WideString): IXmlNode;
 var
 intfSelect : IDomNodeSelect;
 dnResult : IDomNode;
 intfDocAccess : IXmlDocumentAccess;
 doc: TXmlDocument;
 begin
 Result := nil;
 if not Assigned(xnRoot) or not Supports(xnRoot.DOMNode, IDomNodeSelect, intfSelect) then
 Exit;
 dnResult := intfSelect.selectNode(nodePath);

 if Assigned(dnResult) then
 begin
 if Supports(xnRoot.OwnerDocument, IXmlDocumentAccess, intfDocAccess) then
 doc := intfDocAccess.DocumentObject
 else
 doc := nil;
 Result := TXmlNode.Create(dnResult, nil, doc);
 end;
 end;
// --------------------------------------------
 begin
 IDoc:= LoadXMLDocument(edtXMLFileName.Text);
 idoc.ParseOptions := [poPreserveWhiteSpace];
 XPathText := './/path/to/c'; // as per example above, this is my CDATA

 INode := selectnode(IDoc.DocumentElement, xpathtext);

 showmessage(inode.text); // <<< Notice: .text not .XML FAILS for XML with exception.


 end;

What is the correct way to

• Get the CDATA value


• ..while keeping any linefeeds


• I do not need tag or the CDATA tag. Just content.

EDIT
Current state (correction): If I use the .XML value of the IXMLNode, I get the full tag including the CDATA etc:

 <c>![CDATA[My cdata text goes here
It may have linefeed inside
like this
and I need to get all lines WITH linefeeds
]]>
</c>

but if I use the .text, delphi throws an exception.

"Element does not contain a single text node."

Someone suggested here to use XMLTextReader, but I need to query here and there and can't do a forward read only.

My backup plan would be to use a separate function to just remove the XML / CDATA tag returned as above, but it's not pretty.

A CDATA node is different from a Text node. You can't use the IXMLNode.Text property to read the content of a CDATA node. This is documented behavior:

Text is intended for use nodes where the IsTextElement property is true. If IsTextElement is false, then if the node has no children, the value of Text is an empty string.

Setting Text is this case result in a node where IsTextElement is true.

If the node has children (other than a single DOM text node), reading or setting Text causes an exception.

You need to use the IXMLNode.NodeValue property instead, which can read both CDATA and Text content:

ShowMessage(INode.NodeValue);