从控制台应用程序读取网站上的XML文件

Question

What I want to accomplish is reading an xml file from a website ( http://xml.buienradar.nl/ ). I have been reading about what to use, but I can't see the forest for the trees! Should I be using WebRequest, or XmlDocument, or XDocument, or XmlReader, or XmlTextReader, or? I read that XmlDocument and XDocument read the whole file into memory, and XmlReader doesn't. But is that a problem in this case? What if indeed the xml file is huge?

Can someone help me find a way?

Thanks!

Answer 1

To read huge XML without loading all of it into memory, you can use XmlReader class. But please note that this method requires more code than XDocument or even XmlDocument solution.

var h = WebRequest.CreateHttp("http://xml.buienradar.nl/");

using (var r = h.GetResponse())
using (var resp = r.GetResponseStream())    
using (var sr = new StreamReader(resp))    
using (var xr = new XmlTextReader(sr))       
{ 
    while (xr.Read())
    {
        // doing something with xr
        // for example print it's current node value
        Console.WriteLine(xr.Value);
    }
}   

---

If you want to test for large XML file, you can try XML from http://www.ins.cwi.nl/projects/xmark/Assets/standard.gz .

It is over 30 MB gzipped. With this method, XML processing don't require much memory, it even don't wait for whole file to finished downloading.

Test code:

var h = WebRequest.CreateHttp("http://www.ins.cwi.nl/projects/xmark/Assets/standard.gz");

using (var r = h.GetResponse())
using (var resp = r.GetResponseStream())
using (var decompressed = new GZipStream(resp, CompressionMode.Decompress))
using (var sr = new StreamReader(decompressed))
using (var xr = new XmlTextReader(sr))
{
    while (xr.Read())
    {
        // doing something with xr
        // for example print it's current node value
        Console.WriteLine(xr.Value);
    }
}

Answer 2

XmlTextReader provides a faster mechanism for reading xml.

string url="http://xml.buienradar.nl/";

XmlTextReader xml=new XmlTextReader(url);

while(xml.Read())
{
   Console.WriteLine(xml.Value);
}