Hi Justin,
From your description, you want to extract some certain values from an XML
document. In .net framework, there is quite rich API support for XML query
and processing. Here you have three different possible means to do it:
1. Use the xmlreader as you've tried, this is a memory efficient approahc,
but maybe more difficult to code(when xml is complex)
2. use XmlDocument + Xpath query, this is quite simple code
3. If you can use .NET 3.5, then "Linq to XML" is quite a good weapon you
can utilize
Here I've produced sample code (extracting the elements you want) for all
of the 3 approaches mentioned above:
===========using XML Reader================
private void btnReader_Click(object sender, EventArgs e)
{
StreamReader sr = new StreamReader(@"..\..\test.xml",
Encoding.UTF8);
XmlReader xr = XmlReader.Create(sr);
List<stringpaths = new List<string>();
while (xr.Read())
{
if (xr.IsStartElement("AppMode"))
{
MessageBox.Show(xr.GetAttribute("Type"));
}else if(xr.IsStartElement("CurrentFolder"))
{
MessageBox.Show(xr.GetAttribute("Path"));
}
else if (xr.IsStartElement("FilePath"))
{
paths.Add(xr.GetAttribute("Path"));
}
}
MessageBox.Show("paths count: " + paths.Count);
sr.Close();
}
=====================
========USE XML document + xpath query==============
private void btnXmlDoc_Click(object sender, EventArgs e)
{
XmlDocument doc = new XmlDocument();
doc.Load(@"..\..\test.xml");
string type =
doc.SelectSingleNode("/AppMode").Attributes["Type"].Value;
string curfolder =
doc.SelectSingleNode("/AppMode/CurrentFolder").Attributes["Path"].Value;
XmlNodeList files = doc.SelectNodes("//FilePath");
List<stringpaths = new List<string>();
foreach (XmlNode pnode in files)
{
paths.Add(pnode.InnerText);
}
MessageBox.Show("type: " + type + "\r\n"
+ "current folder: " + curfolder + "\r\n"
+ "paths count: " + paths.Count);
}
==============================
============ use LINQ TO XML ===================
private void btnLinq_Click(object sender, EventArgs e)
{
StreamReader sr = new StreamReader(@"..\..\test.xml",
Encoding.UTF8);
XDocument xdoc = XDocument.Load(sr);
sr.Close();
string type = xdoc.Element("AppMode").Attribute("Type").Value;
var cfs = from cf in xdoc.Descendants("CurrentFolder")
select cf.Attribute("Path").Value;
string curfolder = cfs.First();
var paths = from fp in xdoc.Descendants("FilePath")
select fp.Value;
List<stringfpaths = paths.ToList();
MessageBox.Show("type: " + type + "\r\n"
+ "current folder: " + curfolder + "\r\n"
+ "paths count: " + fpaths.Count);
}
=============================
if you want to know more about LINQ to XML, please have a look at the MSDN
reference:
#.NET Language-Integrated Query for XML Data
http://msdn.microsoft.com/en-us/library/bb308960.aspx
Sincerely,
Steven Cheng
Microsoft MSDN Online Support Lead
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--------------------
>From: "Justin" <No**@None.com>
Subject: New to XML. Need help reading XML.
Date: Sat, 26 Jul 2008 00:24:30 -0700
>
Here's my XML:
<?xml version="1.0" ?>
<AppMode Type="Network">
<CurrentFolder Path="c:\tabs">
<Tabs>
<FilePath>tabs\Justin.tab</FilePath>
<FilePath>tabs\Julie.tab</FilePath>
*****There could be 1 of these or 100....quantity can change*****
</Tabs>
</CurrentFolder>
</AppMode>
All I need to do is load "Network" and "c:\tabs" into variables. Then
each
>FilePath goes into an array.
The following code gives me everything but Julie.tab. It only gives me
one
>of the FilePaths. I'm not even sure if this is the right/best way to do
this:
Dim XMLReader As XmlTextReader = New XmlTextReader("")
XMLReader.WhitespaceHandling = WhitespaceHandling.None
XMLReader.Read()
XMLReader.Read()
MsgBox(XMLReader.GetAttribute("Type"))
XMLReader.Read()
MsgBox(XMLReader.GetAttribute("Path"))
XMLReader.Read()
While Not XMLReader.EOF *****Why isn't this looping?
XMLReader.Read()
If Not XMLReader.IsStartElement() Then
Exit While
End If
MsgBox(XMLReader.ReadElementString("FilePath"))
End While
XMLReader.Close()
Any help would be greatly appreciated!
