Consider an XML as below;
<Book>
<BookItem ISBN="SKS84747"><![CDATA[20]]> </BookItem>
<BookItem ISBN="LHKGOI84747"><![CDATA[50]]> </BookItem>
<BookItem ISBN="PUOT84747"><![CDATA[20]]> </BookItem>
</Book>
This code gives me all the CDATA sections,
var value = from v in x.Descendants("BookItem").OfType<XCData>()
select (string)v.Value;
In order to get CDATA of any particular node based on where clause we need to execute below query as,
var value = x.DescendantNodes().OfType<XCData>()
.Where(m => m.Parent.Name == "BookItem" && m.Parent.Attribute("ISBN").Value == "PUOT84747")
.ToList();
This statement will return all the CDATA sections matching in where clause.
To get the single item just replace .ToList() with .Select(cdata => cdata.Value.ToString());
var value = x.DescendantNodes().OfType<XCData>()
.Where(m => m.Parent.Name == "BookItem" && m.Parent.Attribute("ISBN").Value == "PUOT84747")
.Select(cdata => cdata.Value.ToString());