Export DataTable to XML with simple transform

[J055]

Hi

I've been looking into ways of exporting typed DataSets and DataTables to
XML files. I need to manipulate the output before creating the XML file so I
don't think the WriteXml methods will do.

I would like a simple way of transforming a DataTable from e.g.

<accounts>
<account>
<id>1</id>
<name>Bob</name>
</account>
</accounts>

to (id becomes an attribute)

<accounts>
<account id="1">
<name>Bob</name>
</account>
</accounts>

When the XML file is created I would like to validate against a schema and
attach the schema namespace. The file will then be outputted to a client
browser.

I've looked at XmlWriter, TextWriter, XmlSerializer, XslCompiledTransform
classes but I'm not sure which I should use and what the simplest approach
should be.

Any advise/documentation is appreciated.

Thanks
Andrew

[WenYuan Wang [MSFT]]

Hi Andrew,

In my opinion, you may create an XSLT file to convert the xml according to
the structure which you need and then validate the outout xml file by
XmlValidatingReader class. However, if you want to change the xml
structure, you can modify the XSLT file and not necessary to make change in
your code.

Hope this helps.
Sincerely,
Wen Yuan
Microsoft Online Community Support
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[J055]

Hi Walter

Thanks for the tip about using XSLT. I've managed to create a solution
which works for me. I have another question which is kind of related. I want
to use a XSD schema to validate a document. I have no control over the
document but it must match a schema file. I have this code so far which
works but I can't get the ValidationEventHandler to fire if the document
doesn't contain a certain root element. i.e. the root element should be call
<Accountsbut the document still passes validation when the document
contains other element names and structure. Please see the snippets below.
Can you give me some suggestions?
XmlSchemaSet sc = new XmlSchemaSet();
sc.Add(null, filePath + "AccountsImport.xsd");
XmlReaderSettings readerSettings = new XmlReaderSettings();
readerSettings.ValidationType = ValidationType.Schema;
readerSettings.Schemas = sc;
readerSettings.ValidationEventHandler += new
ValidationEventHandler(ValidationCallBack);
XmlReader reader = XmlReader.Create(fileUpload.FileContent, readerSettings);
while (reader.Read());
<?xml version="1.0" encoding="utf-8"?>
<xs:schema id="AccountsSchema" elementFormDefault="qualified"
xmlns:xs="http://www.w3.org/2001/XMLSchema"
xmlns:msdata="urn:schemas-microsoft-com:xml-msdata">
<xs:element name="Accounts">
<xs:complexType>
<xs:all minOccurs="1" maxOccurs="1">
<xs:element name="Account">
<xs:complexType>
<xs:sequence>
....
Thanks
Andrew

[WenYuan Wang [MSFT]]

Hi Andrew,
Thanks for your reply.

Did you mean the ValidationEventHandler cannot fire when the document
contain a wrong root element name (such as "Accountsssssssss").
The code you post in newsgroup is fine. Additionally, I have tested with it
on my side(VS 2005). However, it works fine so far...

I created a test.xml such as
<?xml version="1.0" encoding="utf-8" ?>
<Accountsssssssss>
<Account></Account>
</ Accountsssssssss >

I can get the error message said "The 'Accountsssssssss' element is not
declared."
Have I misunderstood anything here? if not, would you please also post a
xml file which works wrong on your side and tell us which version of .net
framework your application run against. I will perform more research on it.

Have a great day,
Sincerely,
Wen Yuan
Microsoft Online Community Support

[J055]

Hi Wen Yuan

I think it may be my understanding of the schema rules which may be a
problem:

if i add a meaningless xmlns attribute to the root element of the xml file
then the schema in the XmlSchemaSet doesn't test the document. At least
that's what it looks like to me.

<accountsssssss xmlns="urn:test">
<account />
</accountsssssss>

Because the xml document is created by a third party and not coming from a
trusted source I can't be sure that the document won't contain dubious
attributes. I want the schema to be very strict.

Is there a way to force the schema to test any document? I'm using VS2005,
framework v2 .

Many thanks
Andrew

[WenYuan Wang [MSFT]]

Hi Andrew,
Thanks for your reply.

If the xml is not in the namespaceUri of the added schema, then the fact
that we cannot find a schema definition for the elements in the xml
instance is reported as a warning. Warnings are not turned on by default
during validation. The problem is that there is no overload of Validate
that takes in XmlSchemaValidationFlags so that you can turn on Warnings.

You can use a validating reader with the correct validation flags to work
around this issue:

XmlReaderSettings readerSettings = new XmlReaderSettings();
readerSettings.ValidationType = ValidationType.Schema;
//validation flags
readerSettings.ValidationFlags =
XmlSchemaValidationFlags.ReportValidationWarnings;
readerSettings.Schemas = sc;
readerSettings.ValidationEventHandler += new
ValidationEventHandler(ValidationCallBack);
XmlReader reader = XmlReader.Create(fileUpload.FileContent, readerSettings);
while (reader.Read());
......

Hope this helps. Please let me know if you have any further issue on this.
I'm glad to assist you.
Have a great day,
Sincerely,
Wen Yuan
Microsoft Online Community Support