Xpath Debatching in Orchestration -The part 'part' of message 'Message_In_Copy' contained a null value at the end of the construct block

Question

Hi ,
Facing strange issue in Xpath debatching in Orchestration.
Getting following error in construct shape:
The part 'part' of message 'Message_In_Copy' contained a null value at the end of the construct block
Code inside the construct block:
sXpath = System.String.Format("/*[local-name()='Customers' and namespace-uri()='http://Debatch.Customer']/*[local-name()='Customer' and namespace-uri()='http://Debatch.Customer' and position()={0}]", nLoopCount);
System.Diagnostics.Debug.WriteLine(sXpath);
Message_In_Copy= xpath(Message_In, sXpath);
Schema used:
<?xml version="1.0" encoding="utf-16"?>
<xs:schema xmlns="http://Debatch.Customer" xmlns:b="http://schemas.microsoft.com/BizTalk/2003" targetNamespace="http://Debatch.Customer" xmlns:xs="http://www.w3.org/2001/XMLSchema">
<xs:element name="Customers">
<xs:complexType>
<xs:sequence>
<xs:element minOccurs="0" maxOccurs="unbounded" name="Customer">
<xs:complexType>
<xs:sequence>
<xs:element name="name" type="xs:string" />
<xs:element name="id" type="xs:string" />
</xs:sequence>
</xs:complexType>
</xs:element>
</xs:sequence>
</xs:complexType>
</xs:element>
</xs:schema>
Can anyone help me out ? to identify the root cause for above issue.
Thanks,
Kind Regards,
girsh
girishkumar.a

Answer 1

I agree with Shankycheil here, querying XPath will return XMLNode and thus can't be assigned to XMLNode.
But for debatching in Orchestration using Xpath is not a very good idea. 
Because using XPATH loads the complete message in memory(XML Structure) and then performs processing.
This approach is always prone to throwing Out of Memory exception and low in performance also.
Therefore I would suggest you to perform debatching by calling XML Disassembler(XMLReceive) pipeline.
As pipeline works with Stream it will have better performance and you will also get complete control over the messages.
Refer the below samples for debatching using XML Receive pipeline within Orchestration.
Comparrison between XPATH and ReceivePipeline for Debatching:-
De-batching within an orchestration using XPath or calling a pipeline
Debatching within Orchestration using Pipeline-
http://tech-findings.blogspot.in/2013/07/debatchingsplitting-xml-message-in.html 
https://jeremyronk.wordpress.com/2011/10/03/how-to-debatch-into-an-orchestration-with-a-pipeline/
Thanks,
Prashant
Please mark this post accordingly if it answers your query or is helpful.