使用C＃XML文档类修改子节点值

Question

I am a total noob, so apologies, but I have searched everywhere and I'm still stuck.

I am writing a program which will modify 2 XML docs after the user has selected an initial XML document and renamed it. Once the user changes the filename of the first XML (let's call it XML #1), the other two XML docs must have the new filename inserted into specific node values within them (XML #2 and #3).

Each XML doc has multiple "Asset" nodes with exactly the same names, and I need to distinguish the node I want by using a unique UUID value that is present in XML Doc #1.

For both XML #2 and #3, the "Id" nodes contain this same unique UUID. I am parsing XML#1 to get this UUID, and assigning it to a variable called "cpluuid."

Then I am searching XML #2 and #3 for nodes with an "Id" = to "cpluuid", and attempting to modify the correct node that contains the file name to be inserted.

XML Doc #2 - aka var = packing (additional "Asset" nodes omitted)

<Asset>
  <Id>urn:uuid:d0686356-19c7-4bf4-b915-db778c308d1c</Id>
  <AnnotationText>blah</AnnotationText>
  <Hash>5Yf4BV4GZ4qE9EjvtohZ8Rq8M2w=</Hash>
  <Size>21881</Size>
  <Type>text/xml</Type>
  <OriginalFileName>CPL_IMF_JOT_Sample_143.xml</OriginalFileName>
  <HashAlgorithm Algorithm="http://www.w3.org/2000/09/xmldsig#sha1" />
</Asset>

I have had success with updating XML Doc #2 in this manner. The "OriginalFileName" node was successfully updated to the variable value "cpluuid" via this code:

XmlDocument xmlDoc = new XmlDocument();
XmlNamespaceManager ns = new XmlNamespaceManager(xmlDoc.NameTable);
ns.AddNamespace("cplns1", "http://www.smpte-ra.org/schemas/2067-3/2016");
ns.AddNamespace("cplns2", "http://www.w3.org/2001/XMLSchema-instance");
ns.AddNamespace("pklns", "http://www.smpte-ra.org/schemas/2067-2/2016/PKL");
ns.AddNamespace("assetns", "http://www.smpte-ra.org/schemas/429-9/2007/AM");

xmlDoc.PreserveWhitespace = true;
xmlDoc.Load(output);

string cpluuid = xmlDoc.SelectSingleNode("//cplns1:CompositionPlaylist/cplns1:Id", ns).InnerText;

xmlDoc.PreserveWhitespace = true;
xmlDoc.Load(packing);

XmlNodeList nodeList;
XmlNode root = xmlDoc.DocumentElement;

nodeList = root.SelectNodes("descendant::pklns:Asset[pklns:Id=\"" + cpluuid + "\"]", ns);

foreach (XmlNode Asset in nodeList)
{
    Asset["OriginalFileName"].InnerText = (outfile);
}
xmlDoc.PreserveWhitespace = true;
xmlDoc.Save(packing);

However, I am having trouble with XML doc #3, because the node I need to modify ("Path") is nested further down in the tree:

XML Doc #3 - aka var = assetmap

<Asset>
  <Id>urn:uuid:d0686356-19c7-4bf4-b915-db778c308d1c</Id>
  <ChunkList>
    <Chunk>
      <Path>CPL_IMF_JOT_Sample.xml</Path>
      <VolumeIndex>1</VolumeIndex>
      <Offset>0</Offset>
      <Length>21881</Length>
    </Chunk>
  </ChunkList>
</Asset>

So I tried using similar code, but cannot figure out how to drill down further since "Path" is not a sibling of "Asset." This code does not modify the "Path" value. I tried using different XPath syntax, but nothing I know works:

xmlDoc.PreserveWhitespace = true;
xmlDoc.Load(assetmap);

XmlNodeList nodeList2;

nodeList2 = root.SelectNodes("descendant::assetns:Asset[assetns:Id=\"" + cpluuid + "\"]", ns);

foreach (XmlNode Asset in nodeList2)
{
Asset["Path"].InnerText = (outfile);
}
xmlDoc.PreserveWhitespace = true;
xmlDoc.Save(assetmap);

I have tried various using System.Xml.Linq methods as well, but cannot get this to work.

UPDATE#1

Here is how I have been attempting to use XDocument. Seems like it should work, but always returns a Object Reference error.

var xml = XDocument.Load(assetmap);

var node = xml.Descendants("Asset").FirstOrDefault(asset => asset.Element("Id").Value == (cpluuid));

node.SetElementValue("Path", (outfile));

UPDATE #2

My second attempt using XDocument based on awesome feedback from @Juan M. Vergara. Unfortunately, while the code executes with no errors, the XML node does not update to the new value.

XDocument document = XDocument.Load(assetmap);

var assetElements = document.Elements("Asset");

foreach (var asset in assetElements)
{
    var innerElements = asset.Elements("Id");
    var matchingId = innerElements.FirstOrDefault(x => x.Value.Equals(cpluuid));
    if (matchingId == null)
    {
       MessageBox.Show("UUID not found");
       return;
    }

    var chunks = asset.Elements("ChunkList").First().Elements();

    foreach (var chunk in chunks)
    {
       chunk.Elements("Path").First().SetValue(outfile);
    }
}

document.Save(assetmap);

Here is a lager portion of the XML as well, in case there is an issue with namespaces or something else. The "Path" node that nneeds to be updated is the second one in the tree:

<?xml version="1.0" encoding="utf-8"?>
<AssetMap xmlns="http://www.smpte-ra.org/schemas/429-9/2007/AM">
  <Id>urn:uuid:dc59ba55-adfd-4395-bdaa-de54202d014d</Id>
  <Creator>Colorfront Transkoder 2017</Creator>
  <VolumeCount>1</VolumeCount>
  <IssueDate>2018-02-16T20:59:42-00:00</IssueDate>
  <Issuer>Generic</Issuer>
  <AssetList>
    <Asset>
    <Id>urn:uuid:296a656c-3610-4de1-9b08-2aa63245788d</Id>
    <PackingList>true</PackingList>
    <ChunkList>
      <Chunk>
        <Path>PKL_UUID.xml</Path>
        <VolumeIndex>1</VolumeIndex>
        <Offset>0</Offset>
        <Length>3015</Length>
      </Chunk>
    </ChunkList>
    </Asset>
    <Asset>
    <Id>urn:uuid:d0686356-19c7-4bf4-b915-db778c308d1c</Id>
    <ChunkList>
      <Chunk>
        <Path>CPL_IMF_JOT_Sample.xml</Path>
        <VolumeIndex>1</VolumeIndex>
        <Offset>0</Offset>
        <Length>21881</Length>
      </Chunk>
   </ChunkList>
   </Asset>
 </AssetList>
</AssetMap>

UPDATE #3

I'm trying the same method for XML#2 now, but it's not working. I assume because "OriginalFileName" is not the "First" element under "Asset." I'm trying different syntax combos, but nothing seems to work (sequence contains no element errors)

XDocument pkldoc = XDocument.Load(packing);

var pklns = pkldoc.Root.GetDefaultNamespace();
var packingList = pkldoc.Elements(pklns + "PackingList").First(); // this ignores the namespace
var pklassetList = packingList.Elements(pklns + "AssetList").First();
var pklassetElements = pklassetList.Elements(pklns + "Asset");

foreach (var pklasset in pklassetElements)
{
    var innerElements = pklasset.Elements(pklns + "Id");
    var matchingId = innerElements.FirstOrDefault(x => x.Value.Equals(cpluuid));
    if (matchingId == null)
    {
       //MessageBox.Show("UUID not found");
       continue;
    }

    var ofns = pklasset.Elements(pklns + "Asset").First().Elements();

    foreach (var ofn in ofns)
    {
       ofn.Elements(pklns + "OriginalFileName").First().SetValue(outfile);
     }
    }

UPDATE #4

Here are the whole contents of XML #2. The structure is different than XML#3. I only want to update the "OriginalFileName" element in the very last "Asset" tree.

<?xml version="1.0" encoding="UTF-8"?>
<PackingList xmlns="http://www.smpte-ra.org/schemas/2067-2/2016/PKL">
<Id>urn:uuid:296a656c-3610-4de1-9b08-2aa63245788d</Id>
<AnnotationText>IMF_JOT_Sample</AnnotationText>
<IssueDate>2018-02-16T20:59:42-00:00</IssueDate>
<Issuer>Generic</Issuer>
<Creator>Generic</Creator>
<AssetList>
<Asset>
  <Id>urn:uuid:744f36b7-fc7e-4179-8b75-c71c18f98156</Id>
  <AnnotationText>Video_744f36b7-fc7e-4179-8b75-c71c18f98156.mxf</AnnotationText>
  <Hash>8HhnKnLn+Lp/Ik9i94Ml4SXAxH4=</Hash>
  <Size>14568486</Size>
  <Type>application/mxf</Type>
  <OriginalFileName>Video_744f36b7-fc7e-4179-8b75-c71c18f98156.mxf</OriginalFileName>
  <HashAlgorithm Algorithm="http://www.w3.org/2000/09/xmldsig#sha1"/>
</Asset>
<Asset>
  <Id>urn:uuid:bf5438ea-ba58-4ae0-a64a-5d23cee2ebb3</Id>
  <AnnotationText>Audio_bf5438ea-ba58-4ae0-a64a-5d23cee2ebb3.mxf</AnnotationText>
  <Hash>Wg4aEAE5Ji9e14ZyGkvfUUjBwCw=</Hash>
  <Size>4341294</Size>
  <Type>application/mxf</Type>
  <OriginalFileName>Audio_bf5438ea-ba58-4ae0-a64a-5d23cee2ebb3.mxf</OriginalFileName>
  <HashAlgorithm Algorithm="http://www.w3.org/2000/09/xmldsig#sha1"/>
</Asset>
<Asset>
  <Id>urn:uuid:dd5a88d2-ccec-4b22-8584-fda51945c3ea</Id>
  <AnnotationText>Audio_dd5a88d2-ccec-4b22-8584-fda51945c3ea.mxf</AnnotationText>
  <Hash>OwjRFnWZCdKHSZ+3PBXroDhMMlY=</Hash>
  <Size>1458414</Size>
  <Type>application/mxf</Type>
  <OriginalFileName>Audio_dd5a88d2-ccec-4b22-8584-fda51945c3ea.mxf</OriginalFileName>
  <HashAlgorithm Algorithm="http://www.w3.org/2000/09/xmldsig#sha1"/>
</Asset>
<Asset>
  <Id>urn:uuid:9e11458a-71fb-4702-8609-55d2308dcc64</Id>
  <AnnotationText>Sub_9e11458a-71fb-4702-8609-55d2308dcc64.mxf</AnnotationText>
  <Hash>48KyxgwCJVXIdgAGfaNApheQN5M=</Hash>
  <Size>34509</Size>
  <Type>application/mxf</Type>
  <OriginalFileName>Sub_9e11458a-71fb-4702-8609-55d2308dcc64.mxf</OriginalFileName>
  <HashAlgorithm Algorithm="http://www.w3.org/2000/09/xmldsig#sha1"/>
</Asset>
<Asset>
  <Id>urn:uuid:3f57f474-4c81-438e-a67d-1b08fa09a10d</Id>
  <AnnotationText>IMF_JOT_Sample</AnnotationText>
  <Hash>q8TiPkg/3devlN3LXnBhrgkZ968=</Hash>
  <Size>713</Size>
  <Type>text/xml</Type>
  <OriginalFileName>OPL_3f57f474-4c81-438e-a67d-1b08fa09a10d.xml</OriginalFileName>
  <HashAlgorithm Algorithm="http://www.w3.org/2000/09/xmldsig#sha1"/>
</Asset>
<Asset>
  <Id>urn:uuid:d0686356-19c7-4bf4-b915-db778c308d1c</Id>
  <AnnotationText>CPL_IMF_JOT_Sample.xml</AnnotationText>
  <Hash>5Yf4BV4GZ4qE9EjvtohZ8Rq8M2w=</Hash>
  <Size>21881</Size>
  <Type>text/xml</Type>
  <OriginalFileName>CPL_IMF_JOT_Sample.xml</OriginalFileName>
  <HashAlgorithm Algorithm="http://www.w3.org/2000/09/xmldsig#sha1"/>
</Asset>

UPDATE #5

Thanks again Juan for your help. Here is the working solution for XML Doc #2. I know it's not very pretty, but it works.

At some point I'd like to go back and fully digest your last example and combine / cleanup my code the way you have. THANKS!

XDocument pkldoc = XDocument.Load(packing);

var pklns = pkldoc.Root.GetDefaultNamespace();

var pklassetElements = pkldoc.Descendants(pklns + "Asset");

foreach (var pklasset in pklassetElements)
{
    var idElement = pklasset.Descendants(pklns + "Id").First();
    if (!idElement.Value.Equals(cpluuid))
    continue;


    SetNewValue(pklasset, pklns + "OriginalFileName", outfile);

}
void SetNewValue(XElement currentElement, XName elementName, string newValue)
                {
    var matchingElements = currentElement.Descendants(elementName);
    if (matchingElements.Any())
    {
        foreach (var element in matchingElements)
          element.SetValue(newValue);
                    }
                }
                pkldoc.Save(packing);

Answer 1

I just gave it a try and put together some code in a console application example, bear in mind that I do not control all errors in al cases (like element not found...), but I think that it can give you an idea of how you can use System.Xml.Linq.

Hope it helps.

using System;
using System.Linq;
using System.Xml.Linq;

namespace ParsingXML
{

    class Program
    {
        const string _xml =
            @"<Asset>
              <Id>urn:uuid:d0686356-19c7-4bf4-b915-db778c308d1c</Id>
              <ChunkList>
                <Chunk>
                  <Path>CPL_IMF_JOT_Sample.xml</Path>
                  <VolumeIndex>1</VolumeIndex>
                  <Offset>0</Offset>
                  <Length>21881</Length>
                </Chunk>
              </ChunkList>
            </Asset>";

        static void Main(string[] args)
        {
            ReplacePath(
                @"urn:uuid:d0686356-19c7-4bf4-b915-db778c308d1c",
                @"c:\path\to\somefilename.xml"
                );

            Console.WriteLine("Enter to exit...");
            Console.ReadLine();
        }

        static void ReplacePath(string id, string pathToSet)
        {
            XDocument document = XDocument.Parse(_xml);

            var assetElements = document.Elements("Asset");

            foreach (var asset in assetElements)
            {
                var innerElements = asset.Elements("Id");
                var matchingId = innerElements.FirstOrDefault(e => e.Value.Equals(id));
                if (matchingId == null)
                {
                    Console.WriteLine("id not found");
                    return;
                }

                var chunks = asset.Elements("ChunkList").First().Elements();

                foreach (var chunk in chunks)
                {
                    chunk.Elements("Path").First().SetValue(pathToSet);
                }
            }
            var xml = document.ToString();
            Console.WriteLine(xml);

            Console.WriteLine("Enter to exit...");
            Console.ReadLine();
        }
    }
}

And this is the output I get:

<Asset>
  <Id>urn:uuid:d0686356-19c7-4bf4-b915-db778c308d1c</Id>
  <ChunkList>
    <Chunk>
      <Path>c:\path\to\somefilename.xml</Path>
      <VolumeIndex>1</VolumeIndex>
      <Offset>0</Offset>
      <Length>21881</Length>
    </Chunk>
  </ChunkList>
</Asset>
Enter to exit...

Update

Problem is that there are more than one Asset, and as the first one is not matching the first foreach gives a message and stops execution in the return, just replace the return statement by a continue instruction, so the execution does not stop.

In the other hand, you may have to include tha namespace, this is the updated code of my initial ReplacePath function:

    static void ReplacePath(string targetFile, string id, string outfile)
    {
        //XDocument document = XDocument.Parse(_xml);
        XDocument document = XDocument.Load(targetFile);
        // get root namespace to use with rest of element names
        var ns = document.Root.GetDefaultNamespace();

        var assetMap = document.Elements(ns + "AssetMap").First(); // this ignores the namespace
        var assetList = assetMap.Elements(ns + "AssetList").First();
        var assetElements = assetList.Elements(ns + "Asset");

        foreach (var asset in assetElements)
        {
            var innerElements = asset.Elements(ns + "Id");
            var matchingId = innerElements.FirstOrDefault(e => e.Value.Equals(id));
            if (matchingId == null)
            {
                continue;
            }

            var chunks = asset.Elements(ns + "ChunkList").First().Elements();

            foreach (var chunk in chunks)
            {
                var chunkElement = chunk.Elements(ns + "Path").First();
                chunkElement.SetValue(outfile);
            }
        }
        var xml = document.ToString();
        Console.WriteLine(xml);

        Console.WriteLine("writing to file");
        document.Save(targetFile);

        Console.WriteLine("Enter to exit...");
        Console.ReadLine();
    }

I hope this time you got the right answer :).

Answer 2

I preferred to write a different answer, due to the new conditions. Given you have those 2 sample xmls, with different structures but with common nodes, I have given another try using Descendants.

You basically need to find the Asset elements, then check whether the Id matches, and if so, update the Path or OriginalFileName element, try this code:

    private void Run()
    {
        XDocument doc1 = XDocument.Load("xml1.xml");
        XDocument doc2 = XDocument.Load("xml2.xml");
        var id = @"urn:uuid:d0686356-19c7-4bf4-b915-db778c308d1c";

        ReplaceId(doc1, id, "new path");
        ReplaceId(doc2, id, "new path");

        doc1.Save("xml1_new.xml");
        doc2.Save("xml2_new.xml");

        Console.WriteLine("Enter to exit...");
        Console.ReadLine();
    }

    private void ReplaceId(XDocument doc, string id, string newValue)
    {
        var ns = doc.Root.GetDefaultNamespace();
        var assetElements = doc.Descendants(ns + "Asset");

        foreach (var element in assetElements)
        {
            var idElement = element.Descendants(ns + "Id").First();
            if (!idElement.Value.Equals(id))
                continue;

            // for xml model #1
            SetNewValue(element, ns + "Path", newValue);

            // for xml model #2
            SetNewValue(element, ns + "OriginalFileName", newValue);
        }
    }

    private void SetNewValue(XElement currentElement, XName elementName, string newValue)
    {
        var matchingElements = currentElement.Descendants(elementName);
        if (matchingElements.Any())
        {
            foreach (var element in matchingElements)
                element.SetValue(newValue);
        }
    }

Let me now how it goes with this one.

UPDATE

A modification to ReplaceId to know if a replacement has been done:

    private bool ReplaceId(XDocument doc, string id, string newValue)
    {
        var ns = doc.Root.GetDefaultNamespace();
        var assetElements = doc.Descendants(ns + "Asset");
        var result = false;

        foreach (var element in assetElements)
        {
            var idElement = element.Descendants(ns + "Id").First();
            if (!idElement.Value.Equals(id))
                continue;

            // for xml model #1
            SetNewValue(element, ns + "Path", newValue);

            // for xml model #2
            SetNewValue(element, ns + "OriginalFileName", newValue);

            result = true;
        }

        return result;
    }