从大型XML文件中删除节点

Question

i have a large XML document that is to large to be loaded using XmlDocument. i need to go through each child of a node and check it agaisnt a condition, then delete accordingly , then finally save the document.

<root>
<node id="1">
<child delete="false"/>
</node>
<node id="2">
<child delete="true"/>
</node>
</root>

for example i would want to delete node 2, and this process must be repeated hundreds of times.

any help would be appreciated. thanks.

Edit could someone explain how i might go about doing this.

Answer 1

You can use an XmlReader to sequentially read your xml ( ReadOuterXml might be useful in your case to read a whole node at a time). Then use an XmlWriter to write out all the nodes you want to keep.

Answer 2

See this article which compares the performances of xml parsing approaches- http://www.nearinfinity.com/blogs/joe_ferner/performance_linq_to_sql_vs.html

XmlReader turns out to be winner here..

Answer 3

Note, untested and I haven't used XDocument/XElements for awhile, so there may be a typo in here

XDocument xdoc = XDocument.Load("path\\to\\file.xml");
IEnumerable<XElement> elementsToDelete = xdoc.Descendants("node")
   .Where(node => node.Descendants("child")
       .Where(child => child.Attribute("delete") != null && 
       child.Attribute("delete").Value.ToLower() == "true"));
foreach(XElement element in elementsToDelete)
    element.Remove();

xdoc.Save("path\\to\\new\\file.xml");