Read XMLDocument with same Element names - vb.net

Question

I have to read XML document data which is here:
<root>
<cartype>Mercedes</cartype>
<production>2005</production>
<fuel>Diesel</fuel>
<color>Red</color>
<services>
<service>
<year>2006</year>
<km>47800</km>
<city>Stuttgart</city>
</service>
<service>
<year>2007</year>
<km>92125</km>
<city>FFM</city>
</service>
<service>
<km>180420</km>
<year>2009</year>
<city>Hannover</city>
</service>
</services>
<condition>Good</condition>
</root>
Then I read it as such:
Dim cartype As String
Dim fuel As String
Dim production As String
Dim color As String
Dim serviceyear() As String = {"", "", ""}
Dim servicekm() As String = {"", "", ""}
Dim sevicecity() As String = {"", "", ""}
Dim doc As XmlDocument = New XmlDocument()
doc.Load("mercedes.xml")
Dim root As XmlElement = doc.DocumentElement
Dim node As XmlNode = root.SelectSingleNode("production")
If Not node Is Nothing Then production = node.InnerText
node = root.SelectSingleNode("cartype")
If Not node Is Nothing Then cartype = node.InnerText
node = root.SelectSingleNode("fuel")
If Not node Is Nothing Then fuel = node.InnerText
node = root.SelectSingleNode("color")
If Not node Is Nothing Then color = node.InnerText
node = root.SelectSingleNode("services/service/year") '' first service year
If Not node Is Nothing Then serviceyear(0) = node.InnerText
node = root.SelectSingleNode("services/service/year") '' second service year
If Not node Is Nothing Then serviceyear(1) = node.InnerText
Reading nodes with unique element names is OK but I don't know how to read all "services" in array since showed code reads only first service. Services may be from 0 to undefined number of it. Function have to be as fast is possible since large number of xml's have to be readed in what is possible less time.

Answer 1

To read a variable number of <service> elements you will need to use SelectNodes instead of SelectSingleNode:
Dim services = root.SelectNodes("services/service")
You can then iterate over the <service> nodes:
For Each service In services
If service("year") IsNot Nothing Then
Dim year = service("year").InnerText
End If
Next
Personally, I would use LINQ to XML to parse the file (but that may be because I am obsessed with all things LINQ!). Combined with VB.NET's support for XML Literals it makes for some really nice looking code (IMHO).
Here is a complete example you can paste into LINQPad.
Sub Main
' Use XElememt.Load(fileName) to load from file
Dim xml =
<root>
<cartype>Mercedes</cartype>
<production>2005</production>
<fuel>Diesel</fuel>
<color>Red</color>
<services>
<service>
<year>2006</year>
<km>47800</km>
<city>Stuttgart</city>
</service>
<service>
<year>2007</year>
<km>92125</km>
<city>FFM</city>
</service>
<service>
<km>180420</km>
<year>2009</year>
<city>Hannover</city>
</service>
</services>
<condition>Good</condition>
</root>
Dim history = New ServiceHistory() With {
.CarType = xml.<cartype>.Value,
.Production = xml.<production>.Value,
.Fuel = xml.<fuel>.Value,
.Color = xml.<color>.Value,
.Condition = xml.<condition>.Value,
.Services = (
From svc In xml.<services>.<service>
Select New Service() With {
.Year = svc.<year>.Value,
.KM = svc.<km>.Value,
.City = svc.<city>.Value
}
).ToList()
}
history.Dump()
End Sub
' Define other methods and classes here
Public Class ServiceHistory
Public Property CarType As String
Public Property Production As String
Public Property Fuel As String
Public Property Color As String
Public Property Condition As String
Public Property Services As List(Of Service)
End Class
Public Class Service
Public Property Year As String
Public Property KM As String
Public Property City As String
End Class
This gives you the following:

Answer 2

Try linq it will be easier to parse the xml:
It have to be something like that:
xelement = XElement.Load(file);
services = xelement.Element("services").Elements("service");