asked on

Reading Top Five records from XML file ......

Let say I have 100 articles in my XML file and I like to read the top most five articles, how would I do this?
I can read all the articles like this

DataSet ds = new DataSet();
ds.ReadXml(Server.MapPath("Articles.xml"));
DataView dv = ds.Tables[0].DefaultView;

DataList1.DataSource = dv;
DataList1.DataBind();

But I don’t know how would I read top five articles from the xml file.
Thanks

XmlFile
--------------

<?xml version="1.0"?>
<articles>
<article>
<id>050</id>
<title>Article 050 Title</title>
<author>SomeGuy</author>
<dateposted>10/22/2003</dateposted>
<smalldescription>Small description</smalldescription>
<longdescription>Long Description</longdescription>
<code>Some code</code>
</article>
</articles>

C# Code

private void Page_Load(object sender, System.EventArgs e)
{
      DataSet ds = new DataSet();
      ds.ReadXml(Server.MapPath("Articles.xml"));
      DataView dv = ds.Tables[0].DefaultView;

      DataList1.DataSource = dv;
      DataList1.DataBind();
}

ericsDev

**UNTESTESTED**

you can load the records into your DataView and then loop through the DataView and remove all but the rows you want to keep something like this.

for(int x = 0; x < dv.Rows.Count; x++)
{
if(x>=5)
{
dv.Rows[x].Delete();
}
}

I believe this will work unless there is a better way that someone else knows about :)

purpleblob

What about using XPath on the XML first to extract the required subset of article elements - something like

//article[position() <= 5]/*

where 5 is the first five elements

ericsDev

that should work as long as position() is a supported function by MS... I've found that alot of them aren't... you should be able to find that info here: http://msdn.microsoft.com/library/default.asp?url=/library/en-us/xmlsdk/htm/xsd_ref_8nas.asp

ASKER CERTIFIED SOLUTION

purpleblob

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ericsDev

purpleblob: good work, I will keep this method in mind.

adamullah

ASKER

Thanks purpleblob, i also find a good site for XPath. http://www.w3schools.com/xpath/xpath_location.asp

Here is the modified code.

C# codebehind code
------------------------
private void Page_Load(object sender, System.EventArgs e)
{
      XmlDocument xd = new XmlDocument();
      XmlNodeList nl;

      xd.Load(Server.MapPath("Articles.xml"));

      nl = xd.SelectNodes("/articles/article[position() <=3]");

      lstArticles.DataSource = nl;
      lstArticles.DataBind();

}

aspx page code:
-------------------
<asp:datalist id="lstArticles" runat="server">
      <itemtemplate>
            <%# ((System.Xml.XmlNode)Container.DataItem).SelectSingleNode("id").InnerText %>
            <br>
            <%# ((System.Xml.XmlNode)Container.DataItem).SelectSingleNode("title").InnerText %>
      </itemtemplate>
</asp:datalist>

XmlFile
--------
<?xml version="1.0"?>
<articles>
<article>
<id>050</id>
<title>Article 050 Title</title>
<author>SomeGuy</author>
<dateposted>10/22/2003</dateposted>
<smalldescription>Small description</smalldescription>
<longdescription>Long Description</longdescription>
<code>Some code</code>
</article>
</articles>

adamullah

ASKER

purpleblob you got all the points............

purpleblob

Many thanks

Glad to have helped