I have a large XML document that is around 100mb. I need to find attributes for two tags in this document. I can do this by using similar code to the following:
XmlDocument xmlDocument = new XmlDocument ( );
xmlDocument.Load ( "C:\\myxml.xml" );
XmlNode node1 = xmlDocument.SelectSingleNode ( "/data/objects[@type='data type 1']" );
if ( null != node1 )
{
result = node1 [ "Version" ].Value;
}
But doing so loads the entire XML into memory which seems to take around 200mb. Is there anyway I can make this more efficient?
Edit: Lots of nice answers using the XmlTextReader which I have written my code to use now. (It will be more memory efficient, but ugly :).
For performance, SAX is much better than DOM since you actually need only one value. SAX implementation in .NET Framework is XmlTextReader .
You should try to use an XmlReader.
From MSDN :
Like the SAX reader, the XmlReader is a forward-only, read-only cursor. It provides fast, non-cached stream access to the input. It can read a stream or a document. It allows the user to pull data, and skip records of no interest to the application. The big difference lies in the fact that the SAX model is a "push" model, where the parser pushes events to the application, notifying the application every time a new node has been read, while applications using XmlReader can pull nodes from the reader at will.
An example here .
You can use the XmlReader class to do this. A simple but working example that does the same as your code above looks like this:
string result = null;
using (var reader = XmlReader.Create(@"c:\\myxml.xml"))
{
while (reader.Read())
{
if (reader.NodeType == XmlNodeType.Element
&& reader.Depth == 1
&& reader.LocalName == "objects"
&& reader.GetAttribute("type") == "data type 1")
{
result = reader.GetAttribute("Version");
break;
}
}
}
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