XML File - reading and writing

[maw]

Hi, could somebody point me in the right direction for adding, removing
and modifying nodes in an xml file programatically using vb.net (.net
framework 2.0)? I have an xml file in the following format which I need
to be able to add and remove records from. (I can not change this xml
file format.)

<country name="United Kingdom">
<city name="City1">
<street name="15 Street Address">
<details>
<postcode>POS COD</postcode>
<province>Count y1</province>
<c>GB</c>
</details>
</street>
</city>
<city name="City2">
<street name="10 street address">
<details>
<postcode>PST COD</postcode>
<province>Count y</province>
<c>GB</c>
</details>
</street>
</city>
</country>
I am having problems adding a node without overwriting existing data.
For example I can determine if a Country already exists in the XML file
but when I add the City and the Street items to it using the following
code, it replaces existing city and street data in the xml file rather
than appending new elements.

Sub InsertAddress(B yVal doc As XmlDocument)
Dim addresses As XmlNode = doc.DocumentEle ment
Dim country As XmlElement

If country_exists( ) Then
'append
country = doc.SelectSingl eNode("//country[@name='Country']")
Else
country = doc.CreateEleme nt("country")
country.SetAttr ibute("name", "Spain")
End If

Dim city As XmlElement = doc.CreateEleme nt("city")
city.SetAttribu te("name", "City3")

Dim street As XmlElement = doc.CreateEleme nt("street")
street.SetAttri bute("name", "20 Street Address")

Dim details As XmlElement = doc.CreateEleme nt("details")
Dim postcode As XmlElement = doc.CreateEleme nt("postcode")
postcode.InnerT ext = "POS COD"

Dim province As XmlElement = doc.CreateEleme nt("province")
province.InnerT ext = "County3"

Dim c As XmlElement = doc.CreateEleme nt("c")
c.InnerText = "UK"

country.AppendC hild(city)
city.AppendChil d(street)
street.AppendCh ild(details)
details.AppendC hild(postcode)
details.AppendC hild(province)
details.AppendC hild(c)
addresses.Appen dChild(country)
End Sub
Thanks for any help you can give.
Mark.

[RSH]

You can read the XML into a dataset and allow the user to work with that,
saving the results back to XML. Loading and saving data from a dataset is
quite simple and quite effective. In my opinion it is much easier to do
this than work with the XML directly.

Public Overrides Function GetDataSet() As System.Data.Dat aSet

Dim fs As FileStream

Try

fs = New FileStream(MyBa se.FilePath, FileMode.Open)

MyBase.Dataset. ReadXml(fs)

MyBase.Dataset. Tables(0).Prima ryKey = New DataColumn()
{MyBase.Dataset .Tables(0).Colu mns(MyBase.Prim aryKey)}

Return MyBase.Dataset

Catch exc As Exception

WriteToErrorLog (exc)

Finally

fs.Flush()

fs.Close()

End Try

End Function

Public Overrides Function SaveDataset(ByV al oDs As Dataset) As Boolean

Dim fs As System.IO.Strea mWriter

Try

oDs.WriteXml(My Base.FilePath, XmlWriteMode.Wr iteSchema)

fs = New System.IO.Strea mWriter(MyBase. FilePath)

oDs.WriteXml(fs , XmlWriteMode.Wr iteSchema)

Catch exc As Exception

WriteToErrorLog (exc)

Finally

fs.Flush()

fs.Close()

End Try

End Function

End Class

Hope that helps,
Ron

"maw" <ma**@nospam.co mwrote in message
news:46******** *************** @news.zen.co.uk ...

Hi, could somebody point me in the right direction for adding, removing
and modifying nodes in an xml file programatically using vb.net (.net
framework 2.0)? I have an xml file in the following format which I need to
be able to add and remove records from. (I can not change this xml file
format.)

<country name="United Kingdom">
<city name="City1">
<street name="15 Street Address">
<details>
<postcode>POS COD</postcode>
<province>Count y1</province>
<c>GB</c>
</details>
</street>
</city>
<city name="City2">
<street name="10 street address">
<details>
<postcode>PST COD</postcode>
<province>Count y</province>
<c>GB</c>
</details>
</street>
</city>
</country>
I am having problems adding a node without overwriting existing data. For
example I can determine if a Country already exists in the XML file but
when I add the City and the Street items to it using the following code,
it replaces existing city and street data in the xml file rather than
appending new elements.

Sub InsertAddress(B yVal doc As XmlDocument)
Dim addresses As XmlNode = doc.DocumentEle ment
Dim country As XmlElement

If country_exists( ) Then
'append
country = doc.SelectSingl eNode("//country[@name='Country']")
Else
country = doc.CreateEleme nt("country")
country.SetAttr ibute("name", "Spain")
End If

Dim city As XmlElement = doc.CreateEleme nt("city")
city.SetAttribu te("name", "City3")

Dim street As XmlElement = doc.CreateEleme nt("street")
street.SetAttri bute("name", "20 Street Address")

Dim details As XmlElement = doc.CreateEleme nt("details")
Dim postcode As XmlElement = doc.CreateEleme nt("postcode")
postcode.InnerT ext = "POS COD"

Dim province As XmlElement = doc.CreateEleme nt("province")
province.InnerT ext = "County3"

Dim c As XmlElement = doc.CreateEleme nt("c")
c.InnerText = "UK"

country.AppendC hild(city)
city.AppendChil d(street)
street.AppendCh ild(details)
details.AppendC hild(postcode)
details.AppendC hild(province)
details.AppendC hild(c)
addresses.Appen dChild(country)
End Sub
Thanks for any help you can give.
Mark.

[Martin Honnen]

maw wrote:

I am having problems adding a node without overwriting existing data.
For example I can determine if a Country already exists in the XML file
but when I add the City and the Street items to it using the following
code, it replaces existing city and street data in the xml file rather
than appending new elements.

Sub InsertAddress(B yVal doc As XmlDocument)
Dim addresses As XmlNode = doc.DocumentEle ment
Dim country As XmlElement

If country_exists( ) Then
'append
country = doc.SelectSingl eNode("//country[@name='Country']")
Else
country = doc.CreateEleme nt("country")
country.SetAttr ibute("name", "Spain")
End If

Dim city As XmlElement = doc.CreateEleme nt("city")
city.SetAttribu te("name", "City3")

Dim street As XmlElement = doc.CreateEleme nt("street")
street.SetAttri bute("name", "20 Street Address")

Dim details As XmlElement = doc.CreateEleme nt("details")
Dim postcode As XmlElement = doc.CreateEleme nt("postcode")
postcode.InnerT ext = "POS COD"

Dim province As XmlElement = doc.CreateEleme nt("province")
province.InnerT ext = "County3"

Dim c As XmlElement = doc.CreateEleme nt("c")
c.InnerText = "UK"

country.AppendC hild(city)
city.AppendChil d(street)
street.AppendCh ild(details)
details.AppendC hild(postcode)
details.AppendC hild(province)
details.AppendC hild(c)
addresses.Appen dChild(country)
End Sub

With that code that does a lot of AppendChild calls you are only adding
new nodes but you are certainly not able to overwrite stuff that way.
So that code should work fine.
--

Martin Honnen --- MVP XML
http://JavaScript.FAQTs.com/

[mark]

Thanks RSH, can I still use this method with the XML file structure I
posted, i.e using attributes?

RSH wrote:

You can read the XML into a dataset and allow the user to work with that,
saving the results back to XML. Loading and saving data from a dataset is
quite simple and quite effective. In my opinion it is much easier to do
this than work with the XML directly.

Public Overrides Function GetDataSet() As System.Data.Dat aSet

Dim fs As FileStream

Try

fs = New FileStream(MyBa se.FilePath, FileMode.Open)

MyBase.Dataset. ReadXml(fs)

MyBase.Dataset. Tables(0).Prima ryKey = New DataColumn()
{MyBase.Dataset .Tables(0).Colu mns(MyBase.Prim aryKey)}

Return MyBase.Dataset

Catch exc As Exception

WriteToErrorLog (exc)

Finally

fs.Flush()

fs.Close()

End Try

End Function

Public Overrides Function SaveDataset(ByV al oDs As Dataset) As Boolean

Dim fs As System.IO.Strea mWriter

Try

oDs.WriteXml(My Base.FilePath, XmlWriteMode.Wr iteSchema)

fs = New System.IO.Strea mWriter(MyBase. FilePath)

oDs.WriteXml(fs , XmlWriteMode.Wr iteSchema)

Catch exc As Exception

WriteToErrorLog (exc)

Finally

fs.Flush()

fs.Close()

End Try

End Function

End Class

Hope that helps,
Ron

"maw" <ma**@nospam.co mwrote in message
news:46******** *************** @news.zen.co.uk ...

>Hi, could somebody point me in the right direction for adding, removing
and modifying nodes in an xml file programatically using vb.net (.net
framework 2.0)? I have an xml file in the following format which I need to
be able to add and remove records from. (I can not change this xml file
format.)

<country name="United Kingdom">
<city name="City1">
<street name="15 Street Address">
<details>
<postcode>POS COD</postcode>
<province>Count y1</province>
<c>GB</c>
</details>
</street>
</city>
<city name="City2">
<street name="10 street address">
<details>
<postcode>PST COD</postcode>
<province>Count y</province>
<c>GB</c>
</details>
</street>
</city>
</country>
I am having problems adding a node without overwriting existing data. For
example I can determine if a Country already exists in the XML file but
when I add the City and the Street items to it using the following code,
it replaces existing city and street data in the xml file rather than
appending new elements.

Sub InsertAddress(B yVal doc As XmlDocument)
Dim addresses As XmlNode = doc.DocumentEle ment
Dim country As XmlElement

If country_exists( ) Then
'append
country = doc.SelectSingl eNode("//country[@name='Country']")
Else
country = doc.CreateEleme nt("country")
country.SetAttr ibute("name", "Spain")
End If

Dim city As XmlElement = doc.CreateEleme nt("city")
city.SetAttribu te("name", "City3")

Dim street As XmlElement = doc.CreateEleme nt("street")
street.SetAttri bute("name", "20 Street Address")

Dim details As XmlElement = doc.CreateEleme nt("details")
Dim postcode As XmlElement = doc.CreateEleme nt("postcode")
postcode.InnerT ext = "POS COD"

Dim province As XmlElement = doc.CreateEleme nt("province")
province.InnerT ext = "County3"

Dim c As XmlElement = doc.CreateEleme nt("c")
c.InnerText = "UK"

country.AppendC hild(city)
city.AppendChil d(street)
street.AppendCh ild(details)
details.AppendC hild(postcode)
details.AppendC hild(province)
details.AppendC hild(c)
addresses.Appen dChild(country)
End Sub
Thanks for any help you can give.
Mark.