XDocument Get Part of XML File

Question

I have a large xml file and want to get a defined number of <Cooperation> nodes from it. What's the best way to handle this.

Currently, I'm using this code

public string FullCooperationListChunkGet(int part, int chunksize)
{
    StringBuilder output_xml = new StringBuilder();
    IEnumerable<XElement> childList = from el in xml.Elements("Cooperations").Skip(part * chunksize).Take(chunksize) select el;

    foreach (XElement x in childList.Elements())
    {
        output_xml.Append(x.ToString());
    }

    return output_xml.ToString();
}

Skip(part * chunksize).Take(chunksize) doesn't work (seems to be only valid for the Cooperations Tag and not the Cooperation Tags)

Can somebody point me in the right direction.

Thanks,
rAyt

Edit:
The Background is this: I'm pushing these xml parts via a webservice to a Blackberry. Unfortunately, the http request size on a blackberry enterprise server is limited to 256 kb by default.

Part of the XML File:

<?xml version="1.0" encoding="utf-8" standalone="yes"?>
<Cooperations>
  <Cooperation>
    <CooperationId>xxx</CooperationId>
    <CooperationName>xxx</CooperationName>
    <LogicalCustomers>
      <LogicalCustomer>
        <LogicalCustomerId>xxx</LogicalCustomerId>
        <LogicalCustomerName>xxx</LogicalCustomerName>
        <Customers>
          <Customer>
            <CustomerId>xxx</CustomerId>
            <CustomerName>xxx/CustomerName>
          </Customer>
          <Customer>
            <CustomerId>xxx</CustomerId>
            <CustomerName>xxx</CustomerName>
          </Customer>
        </Customers>
      </LogicalCustomer>
      <LogicalCustomer>
        <LogicalCustomerId>xxx</LogicalCustomerId>
        <LogicalCustomerName>xxx</LogicalCustomerName>
        <Customers>
          <Customer>
            <CustomerId>xxx</CustomerId>
            <CustomerName>xxx</CustomerName>
          </Customer>
          <Customer>
            <CustomerId>xxx</CustomerId>
            <CustomerName>xxx</CustomerName>
          </Customer>
        </Customers>
      </LogicalCustomer>
      <LogicalCustomer>
        <LogicalCustomerId>xxx</LogicalCustomerId>
        <LogicalCustomerName>xxx</LogicalCustomerName>
        <Customers>
          <Customer>
            <CustomerId>xxx</CustomerId>
            <CustomerName>xxx</CustomerName>
          </Customer>
        </Customers>
      </LogicalCustomer>
    </LogicalCustomers>
  </Cooperation>
  <Cooperation>
  ...

Answer 1

For using XDocument , I expect you want something like:

var qry = doc.Root.Elements("Cooperation").Skip(part*chunksize).Take(chunksize);

however, if the data is large , you might have to drop down to XmlReader instead... I'll try to do an example... (update; 512kb probably isn't worth it...)

The problem with your code is that you are using .Elements() here:

foreach (XElement x in childList.Elements())
{
    output_xml.Append(x.ToString());
}

Just remove that:

foreach (XElement x in childList)
{
    output_xml.Append(x.ToString());
}

For info - you are also using query syntax unnecessarily:

IEnumerable<XElement> childList = from el in xml.Elements("Cooperations")
    .Skip(part * chunksize).Take(chunksize) select el;

is 100% identical to:

IEnumerable<XElement> childList = xml.Elements("Cooperations")
    .Skip(part * chunksize).Take(chunksize);

(since the compiler ignores an obvious select , without mapping it to the Select LINQ method)

Answer 2

Do you have an xml document or a fragment, ie do you have more than 1 "Cooperations" nodes? If you have more, which Coopertation's are you expecting to get? From just 1 Cooperations or across multiple, reason for asking is that you have written xml.Element s ("Cooperations").

Wouldn't this do the trick:

xml.Element("Cooperations").Elements("Cooperation").Skip(...).Take(...)

Answer 3

You could do this by using System.Net instead of LINQ, although it would be quite messy. Just to give you an idea on how you can read parts of a http response:

// Get the HTTP response
string url = "http://someurl.com/myxml.xml";
HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create(url);
HttpWebResponse response = (HttpWebResponse)request.GetResponse();
// Build a stream
Stream stream = response.GetResponseStream();
Encoding encode = System.Text.Encoding.GetEncoding("utf-8");
StreamReader reader = new StreamReader( stream, encode );

// Loop the file
Char[] read = new Char[256];
int count = reader.Read( read, 0, 256 );
while (count > 0) {
    String str = new String(read, 0, count);
    count = reader.Read(read, 0, 256);
}
response.Close();
stream.Close();

You can use paging by adjusting the count and simultaneously searching str for XML tags.