XPath -> get unique nodes values from XML doc

[AT76]

Hi all,

I'm working on an ASP app in which I need to load an XML file and the display a dropdownlist which when clicked it shows the unique values for a specific node:

Ex.

<?xml version="1.0"?>
<!-- A fragment of a book store inventory database -->
<bookstore xmlns:bk="urn:samples">
  <book genre="novel" publicationdate="1997" bk:ISBN="1-861001-57-8">
    <title>Pride And Prejudice</title>
    <author>
      <first-name>Jane</first-name>
      <last-name>Austen</last-name>
    </author>
    [b][COLOR=red]<type>fiction</type>[/color][/b]
  </book>
  <book genre="novel" publicationdate="1992" bk:ISBN="1-861002-30-1">
    <title>The Handmaid's Tale</title>
    <author>
      <first-name>Margaret</first-name>
      <last-name>Atwood</last-name>
    </author>
    [b][COLOR=red]<type>fiction</type>[/color][/b]
  </book>
  <book genre="novel" publicationdate="1991" bk:ISBN="1-861001-57-6">
    <title>Emma</title>
    <author>
      <first-name>Jane</first-name>
      <last-name>Austen</last-name>
    </author>
    [b][COLOR=red]<type>romance</type>[/color][/b]
  </book>
  <book genre="novel" publicationdate="1982" bk:ISBN="1-861001-45-3">
    <title>Sense and Sensibility</title>
    <author>
      <first-name>Jane</first-name>
      <last-name>Austen</last-name>
    </author>
    [b][COLOR=red]<type>romance</type>[/color][/b]
  </book>
</bookstore>

I would like my dropdown list to display :

fiction
romance

I'm currently able to display:

fiction
fiction
romance
romance

Here's the code I have:

XmlDocument xDoc = new XmlDocument();
            xDoc.Load(xmlPath);
            [b]XmlNodeList audienceList = xDoc.SelectNodes("/bookstore/book/type");[/b]


            foreach (XmlNode n in audienceList)
            {
                ListItem item = new ListItem(n.InnerText, n.InnerText);
                this.selection.Items.Add(item);
            }

Could someone point me in the write direction as to how to get the unique values for type?

Thank you!

 

[mbiro]

http://forums.microsoft.com/MSDN/ShowPost.aspx?PostID=1608546&SiteID=1

 

[AT76]

Thank you mbiro. I've looked at link you posted. I'm still trying to understand how it works.

A friend email me this reference aswell:

http://geekswithblogs.net/ranganh/archive/2005/04/25/37606.aspx

I tried it andit worked! I will keep trying to understand the example you referenced.

Thank you for your help again!

 

[mbiro]

The filter you referenced doesn't let you order the results from what i can tell. Another way to accomplish this would be to load the xml into a datatable and do a select on it with an order by clause. This would give you the results you wanted in order. Then as you loop through the results, have your c# check the previous before adding it to the listitem to see if it is a repeat. This solution may not be as elegant but it does accomplish the task. I would be interested to know which way is most economical in performance...