xmlns attribute created empty when adding element

Question

I have this xml file:

<?xml version="1.0" encoding="utf-8" standalone="no"?>
<S2SDDIdf:MPEDDIdfBlkDirDeb xmlns:S2SDDIdf="urn:S2SDDIdf:xsd:$MPEDDIdfBlkDirDeb"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="urn:S2SDDIdf:xsd:$MPEDDIdfBlkDirDeb MPEDDIdfBlkDirDeb.xsd">

  <S2SDDIdf:SndgInst>CHASDEFX</S2SDDIdf:SndgInst>
  <S2SDDIdf:RcvgInst>BOFIIE2D</S2SDDIdf:RcvgInst>
  <S2SDDIdf:pacs.003.001.01 xmlns="urn:iso:std:iso:20022:tech:xsd:pacs.003.001.01">


  </S2SDDIdf:pacs.003.001.01>
</S2SDDIdf:MPEDDIdfBlkDirDeb>

I am adding this element under element S2SDDIdf:pacs.003.001.01:

<DrctDbtTxInf>
    <PmtId>
        <EndToEndId>DDIE2EA00033</EndToEndId>
        <TxId>DDITXA00033</TxId>
    </PmtId>
</DrctDbtTxInf>

Here is the code:

// Read pacs.003.001.01 element
XElement bulk = XElement.Parse(File.ReadAllText("_Bulk.txt"));

// Read DrctDbtTxInf element
XElement tx = XElement.Parse(File.ReadAllText("_Tx.txt"));

// Add DrctDbtTxInf element to pacs.003.001.01 element
bulk.Element("{urn:S2SDDIdf:xsd:$MPEDDIdfBlkDirDeb}pacs.003.001.01").Add(tx);

The problem is that element DrctDbtTxInf gets an empty xmlns attribute:

<DrctDbtTxInf xmlns="">

How do I get rid if it? I tried to supply the same namespace as in pacs.003.001.01 in the DrctDbtTxInf element but then it just stays there which break the app that reads the xml.

Answer 1

Yes, you need to supply the namespace recursivly for all new elements:

public static class Extensions
{
    public static XElement SetNamespaceRecursivly(this XElement root,
                                                  XNamespace ns)
    {
        foreach (XElement e in root.DescendantsAndSelf())
        {
            if (e.Name.Namespace == "")
                e.Name = ns + e.Name.LocalName;
        }

        return root;    
    }
}


XNamespace ns = "urn:iso:std:iso:20022:tech:xsd:pacs.003.001.01";

// Add DrctDbtTxInf element to pacs.003.001.01 element
bulk.Element("{urn:S2SDDIdf:xsd:$MPEDDIdfBlkDirDeb}pacs.003.001.01")
    .Add(tx.SetNamespaceRecursivly(ns));

This will result in the following XML:

<S2SDDIdf:MPEDDIdfBlkDirDeb xmlns:S2SDDIdf="urn:S2SDDIdf:xsd:$MPEDDIdfBlkDirDeb" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="urn:S2SDDIdf:xsd:$MPEDDIdfBlkDirDeb MPEDDIdfBlkDirDeb.xsd">
  <S2SDDIdf:SndgInst>CHASDEFX</S2SDDIdf:SndgInst>
  <S2SDDIdf:RcvgInst>BOFIIE2D</S2SDDIdf:RcvgInst>
  <S2SDDIdf:pacs.003.001.01 xmlns="urn:iso:std:iso:20022:tech:xsd:pacs.003.001.01">
    <DrctDbtTxInf>
      <PmtId>
        <EndToEndId>DDIE2EA00033</EndToEndId>
        <TxId>DDITXA00033</TxId>
      </PmtId>
    </DrctDbtTxInf>
  </S2SDDIdf:pacs.003.001.01>
</S2SDDIdf:MPEDDIdfBlkDirDeb>