Question

I have set of XML’s ( varies between 2 and 6) that needs to be processed(traversed and checked for certain data and relations within) – The XML’s have some “Recursive Data”
here is a simple example involving a test data for explanation – 2 files considered as example

      File1.xml:
<some root------standard header not entered for the example----->
<parent>
    <ID>AB-1234</ID>
    <Description>Good book</Description>
    <Date_Created>08-10-2011</Date_Created>
    <child>
          <ID>BC-0001</ID>
          <Description>Nice</Description>
     </child>
</parent>
<parent>
    <ID>BC-0001</ID>
    <Description>Work Together</Description>
    <Date_Created>08-10-2011</Date_Created>
    <child>
          <ID>DC-0011</ID>
          <Description>Happy</Description>
     </child>
</parent>

  File2.xml:
<some root------standard header not entered for the example----->
<parent>
    <ID>DC-0011</ID>
    <Description> book</Description>
    <Date_Created>08-10-2011</Date_Created>
    <child>
          <ID>EF-0001</ID>
          <Description>Nice</Description>
     </child>
  </parent>
  <parent>
    <ID>EF-0001</ID>
    <Description>Work Together</Description>
    <Date_Created>08-10-2011</Date_Created>
    <child>
          <ID>PQ-0011</ID>
          <Description>Happy</Description>
     </child>
  </parent>

code I am using involves 1) loading both the XML files and combining them

  XDocument test1doc = XDocument.Load(@"d:\File1.xml");
  XDocument test2doc = XDocument.Load(@"d:\File2.xml");
  IEnumerable<XElement> testElist1 = test1doc.decendants("parent");
  IEnumerable<XElement> testElist2 = test2doc.decendants("parent");
  IEnumerable<XElement> testElistcombo = testElist1.union(testElist2);

2) use the testElistcombo to navigate the elements using foreach – 2 foreach loops (one for the parent and second for the child)
3) while traversing use an if condition to check whether parent ID and Child ID are equal.
I am able to build the hierarchy – no problem with that.
I was able to print the hierarchy along with the level value of the hierarchy.by including a counter in each of the foreach loops.
my output looks like

  AB-1234[level-0]
     >>BC-0001[level-1]
         >>DC-0011[level-3] 
                ..... and so on.

as i said no problem with that. –

Following is the area where i would like some help:
1) when the number of files increases to more than 2 to a max 6, i am using a union in the following manner

           XDocument test1doc = XDocument.Load(@"d:\File1.xml");
           XDocument test2doc = XDocument.Load(@"d:\File2.xml");
           XDocument test3doc = XDocument.Load(@"d:\File3.xml");
           XDocument test4doc = XDocument.Load(@"d:\File4.xml");
           XDocument test5doc = XDocument.Load(@"d:\File5.xml");
           XDocument test6doc = XDocument.Load(@"d:\File6.xml");
           IEnumerable<XElement> testElist1 = test1doc.decendants("parent");
           IEnumerable<XElement> testElist2 = test2doc.decendants("parent");
           IEnumerable<XElement> testElist3 = test3doc.decendants("parent");
           IEnumerable<XElement> testElist4 = test4doc.decendants("parent");
           IEnumerable<XElement> testElist5 = test5doc.decendants("parent");
           IEnumerable<XElement> testElist6 = test6doc.decendants("parent");

           IEnumerable<XElement> testElistcombo1 = testElist1.union(testElist2);
           IEnumerable<XElement> testElistcombo2 = testElistcombo1.union(testElist3);
           IEnumerable<XElement> testElistcombo3 = testElistcombo2.union(testElist4);
           IEnumerable<XElement> testElistcombo4 = testElistcombo3.union(testElist5);
           IEnumerable<XElement> testElistcombo5 = testElistcombo4.union(testElist6);

and use the testElistcombo5.for processing.
help required: an alternative way to load and combine the XML’s to for processing.

2) The process is resource intensive and take a fair bit of time to complete the hierarchy building
help required: is there an alternative way to process the xml’s for building hierarchy in Recursive Data.

Answer 1

Question 1: you can do this using the Enumerable.Aggregate function to aggregate the elements for each document into one set of elements:

IEnumerable<string> filenames = { "filename1.xml", "filename2.xml" };

IEnumerable<XDocument> documents = filenames.Select(XDocument.Load);
IEnumerable<IEnumerable<XElement>> documentsElements = documents.Select(document => document.Descendants("parent"));
IEnumerable<XElement> elements = documentsElements.Aggregate((working, next) => working.Union(next));