XML file question : The Official Microsoft ASP.NET Forums

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EOJRR1

Member

15 Points

XML file question

Mar 26, 2003 04:53 PM|LINK

I have a question that I hope that you guys can answer. :) I am writing a Class that will be used to produce a XML file (report elements) that will be stored in a SQLServer table which will hold the XML until a printing process (I don't have to worry about this) comes along and prints the forms based on the string of XML that my process has stored in the table. Currently I am going down the route of using the TextWriter to write to a file, but with the rollout of this application there is a possiblility of this being run at the same time, so I am looking at just storing the string in virtual memory until it is stored in the DB. How would I accomplish this, if it can be done? Here is the code I have so far, but I am looking to check to see if my theory is on the right track more than my code at this point. However code help never hurts...

Dim tw As XmlTextWriter
        Dim fs As FileStream


        Try
            tw = New XmlTextWriter(fs, New System.Text.UTF8Encoding())


            tw.Formatting = Formatting.Indented
            tw.Indentation = 4
            tw.WriteStartDocument()
           ....etc

This was working fine when I had an actual file name in the place of fs.

            Dim testing As New XmlDocument()
            testing.Load(fs)

            strLine = testing.OuterXml

This was my theory of getting the XML file to a string... TIA

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joteke

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46284 Points

6896 Posts

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Re: XML file question

Mar 26, 2003 06:22 PM|LINK

You are now using FileStream as target of the XML writing. However you could use MemoryStream instead FileStream. ie. write XML to MemoryStream using XmlTextWriter. Then you could get the XML as string by reading MemoryStream using StreamReader and especially StreamReader's ReadToEnd method that returns contents of the stream to be readed as string.

Thanks,

Teemu Keiski
Finland, EU

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EOJRR1

Member

15 Points

3 Posts

Re: XML file question

Mar 26, 2003 07:30 PM|LINK

Thanks, that seems to work at least while stepping through the code, however I am ending up with an empty string at the end of the process... this is my entire sub, I know I am missing something small.

Public Sub writeHeader()
        Dim strXML As String
        Dim tw As XmlTextWriter
        Dim ms As MemoryStream
        Dim sReader As StreamReader


        Try
            ms = New MemoryStream()
            tw = New XmlTextWriter(ms, New System.Text.UTF8Encoding())


            tw.Formatting = Formatting.Indented
            tw.Indentation = 4
            tw.WriteStartDocument()
            tw.WriteComment("Produced from Class on " & Now.ToString)
            tw.WriteStartElement("Workpaper")


            tw.WriteStartElement("ACCOUNT")
            tw.WriteAttributeString("FUNDNAME", Trim(fundName))
            tw.WriteAttributeString("ORGLONGNAME", Trim(_dsSQL.Tables(0).Rows(0)("ORG_LONG_NAME")))
            tw.WriteAttributeString("ACCOUNTNBR", Trim(_dsSQL.Tables(0).Rows(0)("ACCOUNT_NBR10")))
            tw.WriteAttributeString("ORGMGRNAME", Trim(_dsSQL.Tables(0).Rows(0)("ORG_MANAGER_NAME")))


            tw.WriteEndElement()
            tw.WriteEndDocument()




            sReader = New StreamReader(ms)
            strXML = sReader.ReadToEnd


            tw.Flush()
            tw.Close()


        Catch e As Exception
            RaiseError(e)
        End Try




    End Sub

Thanks.

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ksharkey

Member

249 Points

51 Posts

Re: XML file question

Mar 26, 2003 09:17 PM|LINK

Two code changes should help: 1) Move the Flush to before you create the StreamReader (the TextWriter won't write to the MemoryStream until you either Flush or Close -- which forces a Flush) 2) (aka, the magical one): After flushing, move back to the beginning of the MemoryStream: ms.Position = 0 So, the end result (not including all code, just the relevant parts): tw.WriteEndDocument() tw.Flush() ms.Position = 0 sReader = new StreamReader(ms) strXML = sReader.ReadToEnd() tw.Close()

TTFN - Kent

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joteke

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6896 Posts

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Re: XML file question

Mar 27, 2003 05:17 AM|LINK

Was just going to say that after writing to MemoryStream it's position needs to be reset. Just don't close the XMLTextWriter (call it's Close method) before reading MemoryStream with StreamReader, because calling the close will close the underlying stream (MemoryStream in this case) also and you don't want that (you had it right but just reminded) Ksharkey's code shows exactly what needs to be done.

Thanks,

Teemu Keiski
Finland, EU