xmlTextWriter to Stream to xmldoc produces null stream?

[Steve Gilbey]

I have a dataset from which I need to extract certain columns, format
them into xml and output to an xmldocument object.

From reading various posts on similar subjects, I have come up with
the following test code (using 2 constants, rather than my dataset
values):

Public Sub test()
Dim doc As New XmlDocument
Dim xmlStream As Stream = New MemoryStream
Dim xmlWriter As New XmlTextWriter(xmlStream, Encoding.UTF8)
' Dim xmlWriter As New XmlTextWriter(Console.Out)

xmlWriter.Formatting = Formatting.Indented

xmlWriter.WriteStartDocument()
xmlWriter.WriteStartElement("ENTRY_DTL")
xmlWriter.WriteElementString("ORG_CODE", "10")
xmlWriter.WriteElementString("FISCAL_YR",
XmlConvert.ToString(2003))
xmlWriter.WriteEndElement()
xmlWriter.WriteEndDocument()
Try
doc.Load(xmlStream)
Catch ex As Exception
MsgBox(ex, ex.Message)
End Try
End Sub

However the doc.load throws a 'missing root' exception and, on closer
inspection, xmlStream is a null stream. The commented line shows me
the writer is constructing the xml to Console OK, but it doesnt seem
to go into the MemoryStream at all.

Can anyone offer any assistance to an XML virgin who's struggling.

As an aside, am I just going about this the wrong way and would be
better off applying a dataview to my dataset, to get the required
columns, and then somehow writing that directly to an xmldoc?

Thanks,

[Oleg Tkachenko]

Steve Gilbey wrote:

From reading various posts on similar subjects, I have come up with
the following test code (using 2 constants, rather than my dataset
values):

Public Sub test()
Dim doc As New XmlDocument
Dim xmlStream As Stream = New MemoryStream
Dim xmlStream As MemoryStream = New MemoryStream
Dim xmlWriter As New XmlTextWriter(xmlStream, Encoding.UTF8)
' Dim xmlWriter As New XmlTextWriter(Console.Out)

xmlWriter.Formatting = Formatting.Indented

xmlWriter.WriteStartDocument()
xmlWriter.WriteStartElement("ENTRY_DTL")
xmlWriter.WriteElementString("ORG_CODE", "10")
xmlWriter.WriteElementString("FISCAL_YR",
XmlConvert.ToString(2003))
xmlWriter.WriteEndElement()
xmlWriter.WriteEndDocument()
Try
Insert here
xmlStream.Position=0
doc.Load(xmlStream)
Catch ex As Exception
MsgBox(ex, ex.Message)
End Try

btw, you can write directly to XmlDocument using Chris Lovett's XmlNodeWriter
class (find it in gotdotnet.com).
--
Oleg Tkachenko
http://www.tkachenko.com/blog
Multiconn Technologies, Israel

[Steve Gilbey]

Thanks Oleg,
Your suggestion, plus one from elsewhere got me going.

It seems it wasn't enough to just position the stream, the stream and
the writer also need to be flushed before I got anything into Doc.
Adding this:
xmlWriter.Flush()
xmlStream.Flush()
xmlStream.Position = 0

before the doc.load fixed it. Also note, it needs Position AFTER the
flush. The other way around doesn't work.

However in the meantime, I followed your suggestion and got the
XmlNodeWriter and am now using that instead!

Rgds
Steve

Oleg Tkachenko <oleg@NO_SPAM_PLEASEtkachenko.com> wrote in message news:<e2**************@tk2msftngp13.phx.gbl>...

Steve Gilbey wrote:

From reading various posts on similar subjects, I have come up with
the following test code (using 2 constants, rather than my dataset
values):

Public Sub test()
Dim doc As New XmlDocument
Dim xmlStream As Stream = New MemoryStream

Dim xmlStream As MemoryStream = New MemoryStream

Dim xmlWriter As New XmlTextWriter(xmlStream, Encoding.UTF8)
' Dim xmlWriter As New XmlTextWriter(Console.Out)

xmlWriter.Formatting = Formatting.Indented

xmlWriter.WriteStartDocument()
xmlWriter.WriteStartElement("ENTRY_DTL")
xmlWriter.WriteElementString("ORG_CODE", "10")
xmlWriter.WriteElementString("FISCAL_YR",
XmlConvert.ToString(2003))
xmlWriter.WriteEndElement()
xmlWriter.WriteEndDocument()
Try

Insert here
xmlStream.Position=0

doc.Load(xmlStream)
Catch ex As Exception
MsgBox(ex, ex.Message)
End Try

btw, you can write directly to XmlDocument using Chris Lovett's XmlNodeWriter
class (find it in gotdotnet.com).