XmlTextReader vs. XmlValidatingRe ader

[Ed Bacon]

I am a bit puzzled about the differences between
XmlTextReader and XmlValidatingRe ader. I have been able
to successfully load a DataSet object from and XML file
via the text reader. However, when I replace it (xtr) by
a validating reader (vxtr), the DataSet object is Nothing.
No errors have been indicated by the validating reader
(and the XML file is valid for its embedded <schema> ).

So what gives?

[The real problem I'm trying to solve has to do with
<xs:import>'s in the schema, but that is another post.]
dsResults.Clear ()
' A FileStream is needed to read the XML document.
Dim filename As String = "SmfDg.xml"
Dim fs As New FileStream(file name, FileMode.Open)
Dim xtr As New XmlTextReader(f s)
Try
Dim vxtr As XmlValidatingRe ader = New
XmlValidatingRe ader(xtr)
vxtr.Validation Type = ValidationType. None
Dim xsc As New XmlSchemaCollec tion
xsc.Add
("http://vanguard.com/fima2/TransactionType s.xsd", "C:\\Fim
a2\\Solutions\\ Projects\\Commo n\\DataSets\\Tr ansactions\\"
& "TransactionTyp es.xsd")
xsc.Add
("http://vanguard.com/fima2/SmfDataSet.xsd" , "C:\\Fima2
\\Solutions\\Pr ojects\\Common\ \DataSets\\Smf\ \"
& "SMFDataSet.xsd ")
vxtr.Schemas.Ad d(xsc)

Dim ser As XmlSerializer = New XmlSerializer
(GetType(DataSe t))
'Your results may vary between xtr and vxtr
dsResults = CType(ser.Deser ialize(vxtr),
DataSet)

dgAuditDetail.D ataSource = dsResults
dgAuditDetail.D ataMember = dsResults.Table s
(0).TableName

Catch ex As Exception
Trace.WriteLine (ex.ToString)
Finally
fs.Close()
End Try

[Steven Livingstone]

You don't specify a callback handler to catch any exceptions that are
thrown - so you won't get any messages and you're right, it will be null if
validation fails.

AddHandler reader.Validati onEventHandler, AddressOf Me.ValidationEv entHandle

.. . .

'Display the validation error.
Private Sub ValidationEvent Handle(sender As Object, args As
ValidationEvent Args)
m_success = False
Console.WriteLi ne(ControlChars .CrLf & ControlChars.Ta b & "Validation
error: " & args.Message)
End Sub 'ValidationEven tHandle

.. . .

Steven, XmlInsider
http://venturetogether.com
"Ed Bacon" <Ed********@van guard.com> wrote in message
news:d4******** *************** *****@phx.gbl.. .

I am a bit puzzled about the differences between
XmlTextReader and XmlValidatingRe ader. I have been able
to successfully load a DataSet object from and XML file
via the text reader. However, when I replace it (xtr) by
a validating reader (vxtr), the DataSet object is Nothing.
No errors have been indicated by the validating reader
(and the XML file is valid for its embedded <schema> ).

So what gives?

[The real problem I'm trying to solve has to do with
<xs:import>'s in the schema, but that is another post.]
dsResults.Clear ()
' A FileStream is needed to read the XML document.
Dim filename As String = "SmfDg.xml"
Dim fs As New FileStream(file name, FileMode.Open)
Dim xtr As New XmlTextReader(f s)
Try
Dim vxtr As XmlValidatingRe ader = New
XmlValidatingRe ader(xtr)
vxtr.Validation Type = ValidationType. None
Dim xsc As New XmlSchemaCollec tion
xsc.Add
("http://vanguard.com/fima2/TransactionType s.xsd", "C:\\Fim
a2\\Solutions\\ Projects\\Commo n\\DataSets\\Tr ansactions\\"
& "TransactionTyp es.xsd")
xsc.Add
("http://vanguard.com/fima2/SmfDataSet.xsd" , "C:\\Fima2
\\Solutions\\Pr ojects\\Common\ \DataSets\\Smf\ \"
& "SMFDataSet.xsd ")
vxtr.Schemas.Ad d(xsc)

Dim ser As XmlSerializer = New XmlSerializer
(GetType(DataSe t))
'Your results may vary between xtr and vxtr
dsResults = CType(ser.Deser ialize(vxtr),
DataSet)

dgAuditDetail.D ataSource = dsResults
dgAuditDetail.D ataMember = dsResults.Table s
(0).TableName

Catch ex As Exception
Trace.WriteLine (ex.ToString)
Finally
fs.Close()
End Try

[Ed Bacon]

I am sorry I did not paste in all of the code. I do (did)
have a ValidationEvent Handler. It is not called (even if
I set the ValidationType to something other than None),
and that is the puzzle. No event, no exception but
dsResult is Nothing.

Again sorry I did excluded that detail.
Ed

-----Original Message-----
You don't specify a callback handler to catch any exceptions that arethrown - so you won't get any messages and you're right, it will be null ifvalidation fails.

AddHandler reader.Validati onEventHandler, AddressOf Me.ValidationEv entHandle