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Using XPath to read XML data

I need to read an XML file and retrieve a list it contains, then iterate through it.

Can I do this with XPath?

Could someone show me how?

thanks,
newbieweb

HooKooDooKu

XPath is a way of selecting (an) xml node(s). Basically, it's sort of like a query language for an XML file.
http://msdn.microsoft.com/en-us/library/ms256086.aspx

As to how to use it, I've used it using Microsoft's DOM (Document Object Model) of access to an XML file.
http://msdn.microsoft.com/en-us/library/ms753804(VS.85).aspx

When I was using XPath, Microsofts XML reader was at version 4, so the crude code snippet below (written in VB6) is using version 4 (msxml4.dll).

Dim Doc As MSXML2.DOMDocument40
Dim RootNode as MSXML2.IXMLDOMElement 
Dim NodeList As MSXML2.IXMLDOMNodeList
Dim Node As MSXML2.IXMLDOMElement
Dim XPathString as String
 
    Set Doc = New DOMDocument40
    Doc.async = False
    Doc.Load(FileName)
    Call Doc.setProperty("SelectionLanguage", "XPath")    'Allow XPath Queries
 
    Set RootNode = Doc.documentElement
    XPathString = 'Set some query value here
    Set NodeList = RootNode.selectNodes( XPathString )
    Set Node = NodeList.nextNode
    Do Until Node Is Nothing
        'Do stuff with Node object such as 
        'Node.getAttribute( Attribute Name here )
        Set Node = NodeList.nextNode
    Loop

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Toms Edison

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Faizan Sarwar

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curiouswebster

ASKER

HooKooDooKu,

Could you do this in C#?

newbieweb

Toms Edison

Samples below are in C#
http://www.java2s.com/Code/CSharp/XML/XPathQueryDemo.htm
http://www.codeproject.com/KB/cpp/myXPath.aspx

HooKooDooKu

I'm not a C# programmer, but by pulling up a C# editor, it looks like the following code would be functionally equivilent.

using System.Xml    //Add Xml capability to the code
 
...
 
XmlDocument Doc;
Doc.Load( FileName );
XmlElement RootNode = Doc.DocumentElement;
String XPathString = "What ever XPath Query you Need";
XmlNodeList NodeList = RootNode.SelectNodes( XPathString );
for( int i = 0; i < NodeList.Count; i++ )
{
    XmlNode Node = NodeList.Item(i);
    //Do Stuff with Node Here
}

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curiouswebster

ASKER

OK. Now I have the C# code compiling and finding the document okay. But I'm not sure what to use for XPathString.

I need to get all records where

RecordLocator = "YVRSEA"
and need to extract FName and LName for each Passenger record.

How do i do this?

newbieweb

private void PopulatePage()
{
XmlDocument Doc = new XmlDocument();
Doc.Load( @"C:\MyWork\Test\BlankASPTest\testdata\reservation.xml");
XmlElement RootNode = Doc.DocumentElement;
String XPathString = "What ever XPath Query you Need";
XmlNodeList NodeList = RootNode.SelectNodes( XPathString );
for( int i = 0; i < NodeList.Count; i++ )
{
XmlNode Node = NodeList.Item(i);
//Do Stuff with Node Here
}
}

HooKooDooKu

What does the XML look like (sort of hard to build a database query without knowing the structure of the database)?

curiouswebster

ASKER

<?xml version="1.0" encoding="UTF-8" ?>

<FindResByLocatorResponse>
<TransactionID>TEST-031219161726</TransactionID>
<PNR>
<RecordLocator>YVRSEA</RecordLocator>
<Type>0</Type>
<Header>Regular</Header>
<Passenger>
<LName>METHENY</LName>
<FName>PAT</FName>
<Type>ADT</Type>
<PassengerNumber>1.1</PassengerNumber>
<FFN>
<Number>098745341</Number>
<Type>AS</Type>
<AwardLevel>1</AwardLevel>
</FFN>
<ExistingBagCount>0</ExistingBagCount>
<MaxFreeBagCount>2</MaxFreeBagCount>
<StartPassenger/>
<Seat>
<Number>40-C</Number>
</Seat>
<CouponBook>
<FName>PAT</FName>
<LName>METHENY</LName>
<Coupon>
<Carrier>NW</Carrier>
<FlightNumber>711</FlightNumber>
<DeparturePoint>MCO</DeparturePoint>
<ArrivalPoint>DTW</ArrivalPoint>
<CouponNumber>01</CouponNumber>
<Date>19DEC03</Date>
<DepartureTime>2055</DepartureTime>
<Class>Q</Class>
<FareBasis>QEP21NR1</FareBasis>
<ActualStatus>O</ActualStatus>
<SegmentNumber>01</SegmentNumber>
<Status>OK</Status>
<Valid/>
<DepartureCity>Orlando</DepartureCity>
<ArrivalCity>Detroit</ArrivalCity>
</Coupon>
<Coupon>
<Carrier>NW</Carrier>
<FlightNumber>778</FlightNumber>
<DeparturePoint>DTW</DeparturePoint>
<ArrivalPoint>MCO</ArrivalPoint>
<CouponNumber>02</CouponNumber>
<Date>30DEC03</Date>
<DepartureTime>0700</DepartureTime>
<Class>K</Class>
<FareBasis>KEO21NR1</FareBasis>
<ActualStatus>O</ActualStatus>
<Status>OK</Status>
<DepartureCity>Detroit</DepartureCity>
<ArrivalCity>Orlando</ArrivalCity>
</Coupon>
<TicketNumber>0121572614120 </TicketNumber>
<DateOfIssue>23SEP03</DateOfIssue>
<PlaceOfIssue>NORTHWEST AIRLINES/ORBITZ MPLS/ST PAUL MN </PlaceOfIssue>
<FormOfPayment>VI</FormOfPayment>
<FOPType>CC</FOPType>
<Fare>
<Base> 257.68</Base>
<Total> 290.50</Total>
<Currency>USD</Currency>
<Tax>
<Value>US</Value>
<Type> 19.32</Type>
</Tax>
<Tax>
<Value>ZP</Value>
<Type> 6.00</Type>
</Tax>
<Tax>
<Value>XF</Value>
<Type> 7.50</Type>
</Tax>
<Calculation></Calculation>
<CalculationWithTaxes></CalculationWithTaxes>
</Fare>
<EndorsementRestrictions>NON-REFUNDABLE//PENALTY FOR CHANGES </EndorsementRestrictions>
</CouponBook>
<NameFieldStatus></NameFieldStatus>
</Passenger>
<Passenger>
<LName>SCOFIELD</LName>
<FName>JOHN</FName>
<Type>ADT</Type>
<PassengerNumber>2.1</PassengerNumber>
<FFN>
<Number>880932850434</Number>
<Type>CO</Type>
<AwardLevel>1</AwardLevel>
</FFN>
<ExistingBagCount>0</ExistingBagCount>
<MaxFreeBagCount>2</MaxFreeBagCount>
<Seat>
<Number>40-D</Number>
</Seat>
<CouponBook>
<FName>JOHN</FName>
<LName>SCOFIELD</LName>
<Coupon>
<Carrier>NW</Carrier>
<FlightNumber>711</FlightNumber>
<DeparturePoint>MCO</DeparturePoint>
<ArrivalPoint>DTW</ArrivalPoint>
<CouponNumber>01</CouponNumber>
<Date>19DEC03</Date>
<DepartureTime>2055</DepartureTime>
<Class>Q</Class>
<FareBasis>QEP21NR1</FareBasis>
<ActualStatus>O</ActualStatus>
<SegmentNumber>01</SegmentNumber>
<Status>OK</Status>
<Valid/>
<DepartureCity>Orlando</DepartureCity>
<ArrivalCity>Detroit</ArrivalCity>
</Coupon>
<Coupon>
<Carrier>NW</Carrier>
<FlightNumber>778</FlightNumber>
<DeparturePoint>DTW</DeparturePoint>
<ArrivalPoint>MCO</ArrivalPoint>
<CouponNumber>02</CouponNumber>
<Date>30DEC03</Date>
<DepartureTime>0700</DepartureTime>
<Class>K</Class>
<FareBasis>KEO21NR1</FareBasis>
<ActualStatus>O</ActualStatus>
<Status>OK</Status>
<DepartureCity>Detroit</DepartureCity>
<ArrivalCity>Orlando</ArrivalCity>
</Coupon>
<TicketNumber>0121572614120 </TicketNumber>
<DateOfIssue>23SEP03</DateOfIssue>
<PlaceOfIssue>NORTHWEST AIRLINES/ORBITZ MPLS/ST PAUL MN </PlaceOfIssue>
<FormOfPayment>VI</FormOfPayment>
<FOPType>CC</FOPType>
<Fare>
<Base> 257.68</Base>
<Total> 290.50</Total>
<Currency>USD</Currency>
<Tax>
<Value>US</Value>
<Type> 19.32</Type>
</Tax>
<Tax>
<Value>ZP</Value>
<Type> 6.00</Type>
</Tax>
<Tax>
<Value>XF</Value>
<Type> 7.50</Type>
</Tax>
<Calculation></Calculation>
<CalculationWithTaxes></CalculationWithTaxes>
</Fare>
<EndorsementRestrictions>NON-REFUNDABLE//PENALTY FOR CHANGES </EndorsementRestrictions>
</CouponBook>
<NameFieldStatus></NameFieldStatus>
</Passenger>
<Passenger>
<LName>COLTRANE</LName>
<FName>JOHN</FName>
<Type>ADT</Type>
<PassengerNumber>2.1</PassengerNumber>
<FFN>
<Number>338847119</Number>
<Type>NW</Type>
<AwardLevel>1</AwardLevel>
</FFN>
<ExistingBagCount>0</ExistingBagCount>
<MaxFreeBagCount>2</MaxFreeBagCount>
<Seat>
<Number>40-E</Number>
</Seat>
<CouponBook>
<FName>JOHN</FName>
<LName>COLTRANE</LName>
<Coupon>
<Carrier>NW</Carrier>
<FlightNumber>711</FlightNumber>
<DeparturePoint>MCO</DeparturePoint>
<ArrivalPoint>DTW</ArrivalPoint>
<CouponNumber>01</CouponNumber>
<Date>19DEC03</Date>
<DepartureTime>2055</DepartureTime>
<Class>Q</Class>
<FareBasis>QEP21NR1</FareBasis>
<ActualStatus>O</ActualStatus>
<SegmentNumber>01</SegmentNumber>
<Status>OK</Status>
<Valid/>
<DepartureCity>Orlando</DepartureCity>
<ArrivalCity>Detroit</ArrivalCity>
</Coupon>
<Coupon>
<Carrier>NW</Carrier>
<FlightNumber>778</FlightNumber>
<DeparturePoint>DTW</DeparturePoint>
<ArrivalPoint>MCO</ArrivalPoint>
<CouponNumber>02</CouponNumber>
<Date>30DEC03</Date>
<DepartureTime>0700</DepartureTime>
<Class>K</Class>
<FareBasis>KEO21NR1</FareBasis>
<ActualStatus>O</ActualStatus>
<Status>OK</Status>
<DepartureCity>Detroit</DepartureCity>
<ArrivalCity>Orlando</ArrivalCity>
</Coupon>
<TicketNumber>0121572614120 </TicketNumber>
<DateOfIssue>23SEP03</DateOfIssue>
<PlaceOfIssue>NORTHWEST AIRLINES/ORBITZ MPLS/ST PAUL MN </PlaceOfIssue>
<FormOfPayment>VI</FormOfPayment>
<FOPType>CC</FOPType>
<Fare>
<Base> 257.68</Base>
<Total> 290.50</Total>
<Currency>USD</Currency>
<Tax>
<Value>US</Value>
<Type> 19.32</Type>
</Tax>
<Tax>
<Value>ZP</Value>
<Type> 6.00</Type>
</Tax>
<Tax>
<Value>XF</Value>
<Type> 7.50</Type>
</Tax>
<Calculation></Calculation>
<CalculationWithTaxes></CalculationWithTaxes>
</Fare>
<EndorsementRestrictions>NON-REFUNDABLE//PENALTY FOR CHANGES </EndorsementRestrictions>
</CouponBook>
<NameFieldStatus></NameFieldStatus>
</Passenger>
<Segment>
<Type>0</Type>
<Status>HK</Status>
<FlightNumber>0711</FlightNumber>
<DeparturePoint>MCO</DeparturePoint>
<ArrivalPoint>DTW</ArrivalPoint>
<DepartureDate>20MAY04</DepartureDate>
<DepartureTime>1025</DepartureTime>
<ArrivalDate>20MAY04</ArrivalDate>
<ArrivalTime>1243</ArrivalTime>
<Class>Q</Class>
<Index>01</Index>
<StopoverCity></StopoverCity>
<BucketTypes></BucketTypes>
<BoardTime>2055</BoardTime>
<Carrier>NW</Carrier>
<DepartureGate>G14</DepartureGate>
<ArrivalGate>D14</ArrivalGate>
<EquipmentCode>755</EquipmentCode>
<FlightStatus>ON TIME</FlightStatus>
<DepartureCity>Orlando</DepartureCity>
<ArrivalCity>Atlanta</ArrivalCity>
<UpgradeStatus>0</UpgradeStatus>
<SelectSeatEligible/>
<ScheduleChange/>
</Segment>
<SeatsAutoAssigned/>
</PNR>
<Result>1</Result>
</FindResByLocatorResponse>

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HooKooDooKu

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