About DTD Entities

[bheem]

I have a few questions about DTD ENTITY. I would appreciate any help.
1. Is there any equivalent of this in xsd? Suppose I want to use the
same string in multiple places in an xml file, is it possible to do
without DTD entities?

e.g. Consider two elements like this which are present in my xml file.
<AddValue>value 1</AddValue>

<CheckValue>val ue1</CheckValue>

By defining <!ENTITY val "value1"> I can use

<AddValue>&val; </AddValue>
and <CheckValue>&va l;</CheckValue>.

This will make sure that I can change value1 to value2 in just one
place and the other references will pick it up.

But everyone says that DTD is outdated. So is there any other way to
achieve this in XML?

2. If I have a code like above in an XML file and I use
XmlDataDocument Doc = new XmlDataDocument ();
Doc.Load(file); //where file is the name of the xml file
All the entity references are correctly resolved.

However, if I have the xml document stored as a string and then I use

XmlDataDocument Doc = new XmlDataDocument ();
Doc.LoadXml(szX mlString); //where szXmlString is the string that
contains
//the xml text
the code throws an exception. Why is that? Is there a way around it?

Thanks in advance.

[Oleg Tkachenko]

bheem wrote:

I have a few questions about DTD ENTITY. I would appreciate any help.
1. Is there any equivalent of this in xsd? Suppose I want to use the
same string in multiple places in an xml file, is it possible to do
without DTD entities? Not really. You can keep using entities, XmlSchema doesn't pretend to
substitute DTD at this point, instead Schema is fully focused on the
content model definition.
2. If I have a code like above in an XML file and I use
XmlDataDocument Doc = new XmlDataDocument ();
Doc.Load(file); //where file is the name of the xml file
All the entity references are correctly resolved.

However, if I have the xml document stored as a string and then I use

XmlDataDocument Doc = new XmlDataDocument ();
Doc.LoadXml(szX mlString); //where szXmlString is the string that
contains
//the xml text
the code throws an exception. Why is that? Is there a way around it?

Which exception are you talking about? Show us small reproducible sample
of such XML.
--
Oleg Tkachenko
http://www.tkachenko.com/blog
Multiconn Technologies, Israel

[bheem]

Oleg Tkachenko <oleg@NO_SPAM_P LEASEtkachenko. com> wrote in message news:<O4******* *******@tk2msft ngp13.phx.gbl>. ..

Which exception are you talking about? Show us small reproducible sample
of such XML.
Thanks for your reply. Here is a simple sample.

string xmlText;
XmlDataDocument Doc = null;
xmlText = "<?xml version=\"1.0\" encoding=\"utf-8\"?> " +
"<!DOCTYPE TestScript[" +
"<!ENTITY ab \"1000\">" +
"]>" +
"<Root>&ab; </Root>";
Doc = new XmlDataDocument ();
Console.WriteLi ne("{0}", xmlText);
Doc.LoadXml(xml Text);

Essentially I am trying to load the following xml script
<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE TestScript[
<!ENTITY ab "1000">

<Root>&ab;</Root>

If I put the same script in a file and use Doc.Load(file) then it
works fine but the one above throws an exception like this

Unhandled Exception: System.NotSuppo rtedException: Cannot create
entity referenc
es on DataDocument.
at System.Xml.XmlD ataDocument.Cre ateEntityRefere nce(String name)
at System.Xml.XmlL oader.LoadEntit yReferenceNode( )
at System.Xml.XmlL oader.LoadCurre ntNode()
at System.Xml.XmlL oader.LoadChild ren(XmlNode parent)
at System.Xml.XmlL oader.LoadEleme ntNode()
at System.Xml.XmlL oader.LoadCurre ntNode()
at System.Xml.XmlL oader.LoadDocSe quence(XmlDocum ent parentDoc)
at System.Xml.XmlL oader.Load(XmlD ocument doc, XmlReader reader,
Boolean prese
rveWhitespace)
at System.Xml.XmlD ocument.Load(Xm lReader reader)
at System.Xml.XmlD ataDocument.Loa d(XmlReader reader)
at System.Xml.XmlD ocument.LoadXml (String xml)

[Oleg Tkachenko]

bheem wrote:

string xmlText;
XmlDataDocument Doc = null;
xmlText = "<?xml version=\"1.0\" encoding=\"utf-8\"?> " +
"<!DOCTYPE TestScript[" +
"<!ENTITY ab \"1000\">" +
"]>" +
"<Root>&ab; </Root>";
Doc = new XmlDataDocument ();
Console.WriteLi ne("{0}", xmlText);
Doc.LoadXml(xml Text);

Essentially I am trying to load the following xml script
<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE TestScript[
<!ENTITY ab "1000">

<Root>&ab;</Root>

If I put the same script in a file and use Doc.Load(file) then it
works fine but the one above throws an exception like this

Now I see. You have to read such XML through XmlValidatingRe ader then to
be able to control all aspects of entiries resolving, e.g.:

string xmlText;
XmlDataDocument Doc = null;
xmlText = "<?xml version=\"1.0\" encoding=\"utf-8\"?> " +
"<!DOCTYPE TestScript[" +
"<!ENTITY ab \"1000\">" +
"]>" +
"<Root>&ab; </Root>";
Doc = new XmlDataDocument ();
Console.WriteLi ne("{0}", xmlText);
XmlTextReader r = new XmlTextReader(n ew StringReader(xm lText));
XmlValidatingRe ader vr = new XmlValidatingRe ader(r);
vr.ValidationTy pe = ValidationType. None;
Doc.Load(vr);

--
Oleg Tkachenko
http://www.tkachenko.com/blog
Multiconn Technologies, Israel