Question

I have the following rss feed which I would like to query to get all the items with a specific category named subchannel. So far I only managed to get to the first element, but only if it is the first in the list. How would I write the linq query to filter the rss feed to only show items where a certain ‘subchannel’ matches a specific value eg. ‘Accuracy’?

cheers, Chris

protected void Filter() {     var feeds = (from item in doc.Descendants('item')                  where                  item.CategoryValue('Channel') == 'Accomplishment'                   select new                  {                      Title = item.Element('title').Value,                      rssGuid = item.Element('guid').Value,                      description = item.Element('description').Value,                      link = item.Element('link').Value                   }).ToList();      ListView1.DataSource = feeds;     ListView1.DataBind();  } 

Extension Method

public static class ccExtensions {     public static string CategoryValue(this XElement item, string type)     {            var category = item.Elements('category').FirstOrDefault(c => (string)c.Attribute('domain') == type           && !string.IsNullOrEmpty(c.Value));          return category == null ? null : category.Value;      } } 

RSS extract

<item>             <title>Time Mgmt</title>             <description>The following is a list of sample values</description>             <link>http://blah.com/test.aspx</link>             <category domain='Channel'></category>             <category domain='Channel'>Goals</category>             <category domain='SubChannel'></category>             <category domain='SubChannel'>Accountability</category>             <category domain='SubChannel'>Accomplishment</category>             <category domain='SubChannel'>Achievement</category>             <category domain='SubChannel'>Accuracy</category>             <category domain='SubChannel'>Agility</category>             <category domain='SubChannel'>Ambition</category>             <category domain='SubChannel'>Anticipation</category>             <category domain='SubChannel'>Appreciation</category>             <category domain='SubChannel'>Assertiveness</category>             <category domain='SubChannel'>Beauty</category>             <category domain='Type'></category>             <category domain='Type'>Time Management</category>             <guid>5e993951-da49-400b-b8d4-68b95628b9d5</guid> </item> 

Answer 1

The problem is that your CategoryValue is returning a single string, despite the fact that you have multiple categories. I suggest you change it to:

public static class ccExtensions {     public static IEnumerable<string> Categories(this XElement item,                                                  string type)     {         return from category in item.Elements('category')                where (string) category.Attribute('domain') == type                      && !string.IsNullOrEmpty(category.Value)                select category.Value;     } } 

then change your query to:

from item in doc.Descendants('item') where item.Categories('SubChannel').Contains('Accomplishment') select ...