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dotnet xml : Newbie question re column name does not belong to table item
up hill learning curve for me but I would appreciate any help with this probably simple request. I've got a couple of column names in an xml source that my vb.net application can't handle. I know its because there is a ":" in both columns but i don't know of a way to treat the xml as a string, change the column names and then feed the results to an xmltextreader. regards, AndyB this is my xml feed: earthquake data from USGS. http://earthquake.usgs.gov/recenteqsww/eqs1day-M2.5.xml below is the error: An unhandled exception of type 'System.ArgumentException' occurred in system.data.dll Additional information: Column 'geo:lat' does not belong to table item. below is the current code: Const URLString As String = "http://earthquake.usgs.gov/recenteqsww/eqs1day-M2.5.xml" ' We must be able to read the source as a string before it is read as XML ' We need to replace geo:lat with latitude and ' geo:long with longitude Dim reader As XmlTextReader = New XmlTextReader(URLString) ' I guess i need something here to take the reader and feed its contents into a string ' do my replaces and then throw back to a XMLDataset? Dim EarthquakesXMLDS EarthquakesXMLDS = New DataSet EarthquakesXMLDS.ReadXml(reader) Dim EarthquakesXMLDT As DataTable = EarthquakesXMLDS.Tables("item")
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"Andy B" <coastalrocket@yahoo.co.uk> wrote in message news:f1523bf.0501300502.46146cf5@posting.google.com... > columns but i don't know of a way to treat the xml as a string, change > the column names and then feed the results to an xmltextreader. Instead of XmlTextReader, you can subclass XmlTextReader and use that to read-in the XML document and perform the replacements while the XML comes streaming in. Here's an example of such a subclass. - - - GRXmlTextReader.vb Imports System Imports System.IO Imports System.Xml Public Class GeoReplacementXmlTextReader Inherits XmlTextReader Public Sub New( ByVal source As TextReader) MyBase.New( source) End Sub Public Overrides ReadOnly Property Prefix( ) As String Get Dim _prefix As String = MyBase.Prefix If (_prefix = "geo") Then Dim localName As String = MyBase.LocalName If (localName = "lat") Then Return "" Else If (localName = "long") Then Return "" End If End If Return _prefix End Get End Property Public Overrides ReadOnly Property LocalName( ) As String Get Dim prefix As String = MyBase.Prefix Dim _localName As String = MyBase.LocalName If (prefix = "geo") Then If (_localName = "lat") Then Return "latitude" Else If (_localName = "long") Then Return "longitude" End If End If Return _localName End Get End Property Public Overrides ReadOnly Property NamespaceURI( ) As String Get Dim nsURI As String = MyBase.NamespaceURI If (nsURI = "http://www.w3.org/2003/01/geo/wgs84_pos#") Then Dim localName As String = MyBase.LocalName If (localName = "lat") Then Return "" Else If (localName = "long") Then Return "" End If End If Return nsURI End Get End Property End Class - - - [quoted text, click to view] > ' We need to replace geo:lat with latitude and > ' geo:long with longitude > Dim reader As XmlTextReader = New XmlTextReader(URLString) Then the one-line replacement, Dim reader As GeoReplacementXmlTextReader = _ New GeoReplacementXmlTextReader( _ New System.IO.StreamReader( URLString) ) You're also planning to replace the "http://purl.org/dc/elements/1.1/" namespace URI prefix, right? Derek Harmon
Cheers Derek. That is fantastic what you've posted. i'll try it out on
my commute tomorrow. since i'm clueless over the namespace question i might be back here quite quickly. But thanks again, its replies like this which blow me away sometimes. Andy [quoted text, click to view] Derek Harmon wrote:
> "Andy B" <coastalrocket@yahoo.co.uk> wrote in message news:f1523bf.0501300502.46146cf5@posting.google.com... > > columns but i don't know of a way to treat the xml as a string, change > > the column names and then feed the results to an xmltextreader. > > Instead of XmlTextReader, you can subclass XmlTextReader > and use that to read-in the XML document and perform the > replacements while the XML comes streaming in. Here's an > example of such a subclass. > > - - - GRXmlTextReader.vb > Imports System > Imports System.IO > Imports System.Xml > > Public Class GeoReplacementXmlTextReader > Inherits XmlTextReader > > Public Sub New( ByVal source As TextReader) > MyBase.New( source) > End Sub > > Public Overrides ReadOnly Property Prefix( ) As String > Get > Dim _prefix As String = MyBase.Prefix > If (_prefix = "geo") Then > Dim localName As String = MyBase.LocalName > If (localName = "lat") Then > Return "" > Else If (localName = "long") Then > Return "" > End If > End If > Return _prefix > End Get > End Property > > Public Overrides ReadOnly Property LocalName( ) As String > Get > Dim prefix As String = MyBase.Prefix > Dim _localName As String = MyBase.LocalName > If (prefix = "geo") Then > If (_localName = "lat") Then > Return "latitude" > Else If (_localName = "long") Then > Return "longitude" > End If > End If > Return _localName > End Get > End Property > > Public Overrides ReadOnly Property NamespaceURI( ) As String > Get > Dim nsURI As String = MyBase.NamespaceURI > If (nsURI = "http://www.w3.org/2003/01/geo/wgs84_pos#") Then > Dim localName As String = MyBase.LocalName > If (localName = "lat") Then > Return "" > Else If (localName = "long") Then > Return "" > End If > End If > Return nsURI > End Get > End Property > > End Class > - - - > > > ' We need to replace geo:lat with latitude and > > ' geo:long with longitude > > Dim reader As XmlTextReader = New XmlTextReader(URLString) > > Then the one-line replacement, > > Dim reader As GeoReplacementXmlTextReader = _ > New GeoReplacementXmlTextReader( _ > New System.IO.StreamReader( URLString) ) > > You're also planning to replace the "http://purl.org/dc/elements/1.1/" > namespace URI prefix, right? > > > Derek Harmon
Hi Derek,
I tried the code you posted but get an error of 'URI formats are not supported.' when i declare [quoted text, click to view] > > Dim reader As GeoReplacementXmlTextReader = _ It looks like a system.io.streamreader doesn't accept a URL string.> > New GeoReplacementXmlTextReader( _ > > New System.IO.StreamReader( URLString) ) I'll try sorting this out but i thought i'd post back quickly with the error in case anyone knows immediately the solution here. [quoted text, click to view] "digger440uk" <coastalrocket@yahoo.co.uk> wrote in message news:<1107204051.970243.31580@c13g2000cwb.googlegroups.com>...
> Cheers Derek. That is fantastic what you've posted. i'll try it out on > my commute tomorrow. since i'm clueless over the namespace question i > might be back here quite quickly. > > But thanks again, its replies like this which blow me away sometimes. > Andy > > Derek Harmon wrote: > > "Andy B" <coastalrocket@yahoo.co.uk> wrote in message > news:f1523bf.0501300502.46146cf5@posting.google.com... > > > columns but i don't know of a way to treat the xml as a string, > change > > > the column names and then feed the results to an xmltextreader. > > > > Instead of XmlTextReader, you can subclass XmlTextReader > > and use that to read-in the XML document and perform the > > replacements while the XML comes streaming in. Here's an > > example of such a subclass. > > > > - - - GRXmlTextReader.vb > > Imports System > > Imports System.IO > > Imports System.Xml > > > > Public Class GeoReplacementXmlTextReader > > Inherits XmlTextReader > > > > Public Sub New( ByVal source As TextReader) > > MyBase.New( source) > > End Sub > > > > Public Overrides ReadOnly Property Prefix( ) As String > > Get > > Dim _prefix As String = MyBase.Prefix > > If (_prefix = "geo") Then > > Dim localName As String = MyBase.LocalName > > If (localName = "lat") Then > > Return "" > > Else If (localName = "long") Then > > Return "" > > End If > > End If > > Return _prefix > > End Get > > End Property > > > > Public Overrides ReadOnly Property LocalName( ) As String > > Get > > Dim prefix As String = MyBase.Prefix > > Dim _localName As String = MyBase.LocalName > > If (prefix = "geo") Then > > If (_localName = "lat") Then > > Return "latitude" > > Else If (_localName = "long") Then > > Return "longitude" > > End If > > End If > > Return _localName > > End Get > > End Property > > > > Public Overrides ReadOnly Property NamespaceURI( ) As String > > Get > > Dim nsURI As String = MyBase.NamespaceURI > > If (nsURI = "http://www.w3.org/2003/01/geo/wgs84_pos#") > Then > > Dim localName As String = MyBase.LocalName > > If (localName = "lat") Then > > Return "" > > Else If (localName = "long") Then > > Return "" > > End If > > End If > > Return nsURI > > End Get > > End Property > > > > End Class > > - - - > > > > > ' We need to replace geo:lat with latitude and > > > ' geo:long with longitude > > > Dim reader As XmlTextReader = New XmlTextReader(URLString) > > > > Then the one-line replacement, > > > > Dim reader As GeoReplacementXmlTextReader = _ > > New GeoReplacementXmlTextReader( _ > > New System.IO.StreamReader( URLString) ) > > > > You're also planning to replace the > "http://purl.org/dc/elements/1.1/" > > namespace URI prefix, right? > > > >
[quoted text, click to view]
coastalrocket@yahoo.co.uk (Andy B) wrote in message news:<f1523bf.0502051007.10a6f0be@posting.google.com>... > Hi Derek, > I tried the code you posted but get an error of 'URI formats are not > supported.' when i declare > > > Dim reader As GeoReplacementXmlTextReader = _ > > > New GeoReplacementXmlTextReader( _ > > > New System.IO.StreamReader( URLString) ) > It looks like a system.io.streamreader doesn't accept a URL string. > I'll try sorting this out but i thought i'd post back quickly with the > error in case anyone knows immediately the solution here. > > "digger440uk" <coastalrocket@yahoo.co.uk> wrote in message news:<1107204051.970243.31580@c13g2000cwb.googlegroups.com>... > > Cheers Derek. That is fantastic what you've posted. i'll try it out on > > my commute tomorrow. since i'm clueless over the namespace question i > > might be back here quite quickly. > > > > But thanks again, its replies like this which blow me away sometimes. > > Andy > > > > Derek Harmon wrote: > > > "Andy B" <coastalrocket@yahoo.co.uk> wrote in message > > news:f1523bf.0501300502.46146cf5@posting.google.com... > > > > columns but i don't know of a way to treat the xml as a string, > > change > > > > the column names and then feed the results to an xmltextreader. > > > > > > Instead of XmlTextReader, you can subclass XmlTextReader > > > and use that to read-in the XML document and perform the > > > replacements while the XML comes streaming in. Here's an > > > example of such a subclass. > > > > > > - - - GRXmlTextReader.vb > > > Imports System > > > Imports System.IO > > > Imports System.Xml > > > > > > Public Class GeoReplacementXmlTextReader > > > Inherits XmlTextReader > > > > > > Public Sub New( ByVal source As TextReader) > > > MyBase.New( source) > > > End Sub > > > > > > Public Overrides ReadOnly Property Prefix( ) As String > > > Get > > > Dim _prefix As String = MyBase.Prefix > > > If (_prefix = "geo") Then > > > Dim localName As String = MyBase.LocalName > > > If (localName = "lat") Then > > > Return "" > > > Else If (localName = "long") Then > > > Return "" > > > End If > > > End If > > > Return _prefix > > > End Get > > > End Property > > > > > > Public Overrides ReadOnly Property LocalName( ) As String > > > Get > > > Dim prefix As String = MyBase.Prefix > > > Dim _localName As String = MyBase.LocalName > > > If (prefix = "geo") Then > > > If (_localName = "lat") Then > > > Return "latitude" > > > Else If (_localName = "long") Then > > > Return "longitude" > > > End If > > > End If > > > Return _localName > > > End Get > > > End Property > > > > > > Public Overrides ReadOnly Property NamespaceURI( ) As String > > > Get > > > Dim nsURI As String = MyBase.NamespaceURI > > > If (nsURI = "http://www.w3.org/2003/01/geo/wgs84_pos#") > > Then > > > Dim localName As String = MyBase.LocalName > > > If (localName = "lat") Then > > > Return "" > > > Else If (localName = "long") Then > > > Return "" > > > End If > > > End If > > > Return nsURI > > > End Get > > > End Property > > > > > > End Class > > > - - - > > > > > > > ' We need to replace geo:lat with latitude and > > > > ' geo:long with longitude > > > > Dim reader As XmlTextReader = New XmlTextReader(URLString) > > > > > > Then the one-line replacement, > > > > > > Dim reader As GeoReplacementXmlTextReader = _ > > > New GeoReplacementXmlTextReader( _ > > > New System.IO.StreamReader( URLString) ) > > > > > > You're also planning to replace the > > "http://purl.org/dc/elements/1.1/" > > > namespace URI prefix, right? > > > > > > > > > Derek Harmon I found a solution as.. Dim XMLString As String = GetHtmlPageSource(URLString) XMLString = XMLString.Replace("geo:lat", "latitude") XMLString = XMLString.Replace("geo:long", "longitude") XMLString = XMLString.Replace("icbm:latitude", "latitude") XMLString = XMLString.Replace("icbm:longitude", "longitude") Dim stream As StringReader Dim reader As XmlTextReader stream = New StringReader(XMLString) reader = New XmlTextReader(stream) Function GetHtmlPageSource(ByVal url As String, Optional ByVal username As _ String = Nothing, Optional ByVal password As String = Nothing) As String Dim st As System.IO.Stream Dim sr As System.IO.StreamReader Try ' make a Web request Dim req As System.Net.WebRequest = System.Net.WebRequest.Create(url) ' if the username/password are specified, use these credentials If Not username Is Nothing AndAlso Not password Is Nothing Then req.Credentials = New System.Net.NetworkCredential(username, _ password) End If ' get the response and read from the result stream Dim resp As System.Net.WebResponse = req.GetResponse st = resp.GetResponseStream sr = New System.IO.StreamReader(st) ' read all the text in it Return sr.ReadToEnd Catch ex As Exception Return "" Finally ' always close readers and streams sr.Close() st.Close() End Try End Function
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