XDocument和XmlDocument的替代方案，用于在C＃中加载xml文件？

Question

I want to change an attribute inside an xml file using C#.

Here is a sample XML file

<?xml version="1.0" encoding="us-ascii"?>
<Client>
  <Age>25</Age>
  <Weight>50</Weight>
</Client>

I tried loading the xml file using both XmlDocument and XDocument . They both take so much time (more than 5 minutes) to load.

Here is the code I am using to load the file:

string filePath = @"myFile.xml";
XmlDocument xmlData = new XmlDocument();

As per Google, the problem is that XDocument and XmlDocument will load all the DTDs for XML file, and this is why it takes much time. Is there a workaround for this? or maybe any alternative that allows me to change an attribute without loading all the DtDs?

Answer 1

You can control how DTDs are cached, parsed or used for validation with XmlReaderSettings and still use XDocument .

If you can take the time to cache the DTDs and changing them isn't part of your test, you could take the hit once and cache them.

If that's too much time or they aren't available and they aren't needed for your tests, you could skip DTD processing.

using (var reader = XmlReader.Create(_, 
  new XmlReaderSettings
  {
      DtdProcessing = DtdProcessing.Ignore,
      ValidationType = ValidationType.None,
      //DtdProcessing = DtdProcessing.Parse,
      //ValidationType = ValidationType.DTD,
      XmlResolver = new XmlUrlResolver
      {
          CachePolicy = new RequestCachePolicy(RequestCacheLevel.CacheIfAvailable),
          //CachePolicy = new RequestCachePolicy(RequestCacheLevel.NoCacheNoStore),
      }
  }))
{
    var doc = XDocument.Load(reader);
    //…
}

XmlReaderSettings has many other properties that sometimes come in handy.