how to delete all the line items from the file after the first one - linq

Question

I need to delete all the line items <LineItem> from the file which does not suffice with this requirements:
elements in Line Item : <LineItemNumber V="00000000000000000010" /> and <PurchaseOrderNumber V="0100230946|00010" /> have to be matched, another words in integer Line Item Number would be 10 and Purchase order number after pipe line | would be 10. we need to have only one those line Items which are matching this requirement. Sorry, i'm really bad at describing.
<Transmission>
<InterchangeUsageIndicator V="T" />
<Groups>
<Group>
<GroupSenderID V="CCC" />
<TotalNumberOfShipmentsInGroup V="000005" />
<Documents>
<Document>
<DocumentHeader>
<InvoiceChargeType V="T" />
<DocumentType V="ORDER" />
<DocumentProcessingCode C="00" />
<BOLNumber V="BOL2309460180582136" />
<AlternateQuantities>
<AlternateQuantity Quantity="12.0" UOM="PK" UOMType="SQ" Characteristic="" />
</AlternateQuantities>
<Buyer Name="" Q="ZP" ID="COUSPO001">
<AlternateIDs />
</Buyer>
<Seller Name="" Q="2" ID="CNTR">
<AlternateIDs />
</Seller>
<Parties>
<Party PartyType="SF">
<Name V="SHA" />
<LocationID Q="" ID="" />
<AlternateLocationIDs>
<LocationID Q="" ID="SHA" />
</AlternateLocationIDs>
<City V="Shanghai" />
<Country V="CN" />
<LocationPurpose V="" />
</Party>
<Party PartyType="ST">
<Name V="LEB" />
<LocationID Q="" ID="" />
<AlternateLocationIDs>
<LocationID Q="" ID="LEB" />
</AlternateLocationIDs>
<City V="Lebanon" />
<Country V="TN" />
<LocationPurpose V="" />
</Party>
<Party PartyType="VN">
<Name V="YANGZHOU BAOYI SHOES" />
<LocationID Q="" ID="4100000423" />
<AlternateLocationIDs />
<City V="JIANGSU" />
<Country V="CN" />
<LocationPurpose V="" />
</Party>
</Parties>
<DateReferences>
<DR Type="D" Q="ETA" Date="2019-12-19" />
<DR Type="D" Q="EST" Date="2019-11-28" />
</DateReferences>
<ReservedReferences>
<RR Type="R" Q="K6" V="86|SEAL230946" />
<RR Type="R" Q="V3" V="VYG230946|BKG230946" />
</ReservedReferences>
</DocumentHeader>
<Vessel VesselName="VSL230946" VesselNumber="" VesselCountryOfRegistration="" VesselRegistrationNumber="" />
<Equipments>
<Equipment Initial="CNTR" Number="230946" Length="0" Type="" TotalContainerVolume="52.06" />
</Equipments>
<LineItems>
<LineItem>
<LineItemNumber V="00000000000000000010" />
<LineItemType C="LI" />
<TransportationServiceCode Code="" />
<PurchaseOrderNumber V="0100230946|00010" />
<AdditionalReferenceNumber V="" />
<DescriptionMarksAndNumbers>
<CommodityCode Q="" C="M9160" />
<BuyerProductID V="" />
</DescriptionMarksAndNumbers>
<BilledRatedAsQuantity V="0.0" UOM="PA" />
<LadingQuantity V="0.0" UOM="PA" />
<LineItemTotalAmount V="0.0" />
<LineItemWeight V="0.00" />
<LineItemVolume V="0.00" />
</LineItem>
<LineItem>
<LineItemNumber V="00000000000000900001" /> //this one would not work,because it is 900001
<LineItemType C="LI" />
<LineItemSubType C="SCH" />
<TransportationServiceCode Code="" />
<PurchaseOrderNumber V="0100230946|00010" />
<AdditionalReferenceNumber V="" />
<DescriptionMarksAndNumbers>
<CommodityCode Q="" C="M9160" />
<BuyerProductID V="" />
</DescriptionMarksAndNumbers>
<BilledRatedAsQuantity V="24.0" UOM="PA" />
<LadingQuantity V="24.0" UOM="PA" />
<LineItemTotalAmount V="0.0" />
<UserDefinedReferences>
<UDR Type="U" Q="CR" V="22859470896|001|0001" Description="" />
<UDR Type="U" Q="S6" V="|3|20" Description="" />
<UDR Type="U" Q="19" V="M9160|USDS|0001" Description="" />
</UserDefinedReferences>
<LineItemWeight V="2959.54" />
<LineItemVolume V="104.12" />
</LineItem>
<LineItem>
<LineItemNumber V="00000000000000900002" />
<LineItemType C="LI" />
<LineItemSubType C="SCH" />
<TransportationServiceCode Code="" />
<PurchaseOrderNumber V="0100230946|00010" />
<AdditionalReferenceNumber V="" />
<DescriptionMarksAndNumbers>
<CommodityCode Q="" C="M9160" />
<BuyerProductID V="" />
</DescriptionMarksAndNumbers>
<BilledRatedAsQuantity V="24.0" UOM="PA" />
<LadingQuantity V="24.0" UOM="PA" />
<LineItemTotalAmount V="0.0" />
<UserDefinedReferences>
<UDR Type="U" Q="CR" V="22859470902|001|0002" Description="" />
<UDR Type="U" Q="S6" V="|3.5|20" Description="" />
<UDR Type="U" Q="19" V="M9160|USDS|0001" Description="" />
</UserDefinedReferences>
<LineItemWeight V="2959.54" />
<LineItemVolume V="104.12" />
</LineItem>
I tried to start on LINQ: this is where I got so far:
try {
var xDoc = XDocument.Parse(msg.Body);
var xDocument = xDoc.Root.XPathSelectElement("Groups/Group/Documents/Document");
var xLineItems = xDocument.XPathSelectElements("LineItems/LineItem");
var poNumbers = xLineItems.Select(e => (string)e.Element("PurchaseOrderNumber").Attribute("V")).Distinct();
foreach (var poNumber in poNumbers) {
}
msg.Body = xDoc.ToString();

Answer 1

I believe you would like to Delete all LineItem where LineItemNumber!=10 and PurchaseOrderNumber after the Pipe NOT equals 10. You could use Linq to filter the elements that match the purpose and use the Remove method to deletes the selected nodes.
var xDoc = XDocument.Parse(xml);
xDoc.Descendants("LineItem")
.Where(x=> Convert.ToInt32(x.Element("LineItemNumber").Attribute("V").Value)!=10
&& Convert.ToInt32(x.Element("PurchaseOrderNumber").Attribute("V").Value.Split('|')[1])!=10
).Remove();
var result = xDoc.ToString();