Reading an xml file 50 lines at a time

Question

Currently trying to make a method to read in XML files at the moment 50 lines at a time this will be increased to allow larger files to be used in the program.

At the moment i am trying to accomplish this with the following code.

 List<dataclass.DataRecord> list = new List<dataclass.DataRecord>();
 string filename = "FileLocation"
 XmlDocument testing = new XmlDocument();

 //using (StreamReader streamreader = new StreamReader(filename))
 using (XmlTextReader reader = new XmlTextReader(new StringReader(filename)))
 {
   while (reader.Read() != null)
   {
    for (int i = 0; i < 50; i++)
    {
     testing.Load(reader);

     //list.add(line);
     Console.WriteLine(testing);
     //testing.Load(reader);
     }
   }
 }

commented lines are just from previous ideas i used to accomplish my goal and the filename has been taken out as i just prefer not to place that online.

Basically at the moment i keep getting the following error:

Data at the root level is invalid. Line 1, position 1.

So i dunno if I am:

A. Going about this the right way.

B. Is the only way to fix this error is by surrounding the "testing.load" by "root + /root" tags

hope someone can help thank.

You should think of XML like a **Tree** rather than a **Flat file** with lines. A line doesn't make sense in XML, you could be cutting a **node** up if you only read 50 "lines". What are you achieving by doing this? — Belogix, Apr 02 '13 at 11:10
okay ill give that a look over, I am rather new to doing this. — user2169674, Apr 02 '13 at 11:11
to answer you question in what im achieving, I am just trying to load the file gradually rather than all in one go . — user2169674, Apr 02 '13 at 12:36
OK, I've added as an answer as you're not supposed to use comments as a communication method and my idea is a bit longer than a comment. — Belogix, Apr 02 '13 at 12:45

score 0 · Answer 1 · answered Apr 02 '13 at 11:14

0

If you are only trying to load xml into XmlDocument - why not just

 XmlDocument testing = new XmlDocument();
 testing.Load(filename);

answered Apr 02 '13 at 11:14

evgenyl

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I know i could just do that but, but the program maybe needed to load very large files, so this method of loading the file in gradually hopefully should be efficient – user2169674 Apr 02 '13 at 12:22

score 0 · Answer 2 · answered Apr 02 '13 at 12:23

0

If your XML file is really big, you're better off using some sort of pull parser (parses tag-by-tag, attribute-by-attribute, etc) rather than DOM parser (loads whole document during parsing, keeps it in memory).

answered Apr 02 '13 at 12:23

pfyod

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score 0 · Accepted Answer · edited May 23 '17 at 12:13

0

As I explained in my comment XML consists of nodes whereas you are looking at it as though it were a flat-file with lines.

There are a couple of Stackoverflow questions with answers that match what you are trying to do. The real question is "How can you load a large XML file". The answer is to use a stream rather than loading in one big chunk, following on from there you can find lots of resources about using XmlReader.

Couple of pointers to other SO articles:

C# and Reading Large XML Files

Reading large XML documents in .net

Hope that helps!

edited May 23 '17 at 12:13

Community

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answered Apr 02 '13 at 12:45

Belogix

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helps alot, just as you posted i was looking at these links as well from a combination of your comment and pyfods answers. – user2169674 Apr 02 '13 at 13:05

Reading an xml file 50 lines at a time

3 Answers3