/// <summary>
/// Method for retrieving RSS feed information, especially the image of the feed
/// </summary>
/// <param name="feed">Feed whose information to fetch</param>
/// <param name="onGetRSSFeedImageUriCompleted">Action to take when information has been retrieved</param>
/// <param name="onError">Action to take when an error occurs</param>
public static void GetRSSFeedImageUri(RSSFeed feed, Action <Uri, RSSFeed> onGetRSSFeedImageUriCompleted = null, Action <Exception> onError = null)
{
WebClient webClient = new WebClient();
webClient.OpenReadCompleted += delegate(object sender, OpenReadCompletedEventArgs e)
{
try
{
if (e.Error != null)
{
if (onError != null)
{
onError(e.Error);
}
return;
}
XmlReader response = XmlReader.Create(e.Result);
SyndicationFeed rssFeed = SyndicationFeed.Load(response);
if (onGetRSSFeedImageUriCompleted != null)
{
onGetRSSFeedImageUriCompleted(rssFeed.ImageUrl, feed);
}
}
catch (Exception error)
{
if (onError != null)
{
onError(error);
}
}
};
webClient.OpenReadAsync(new Uri(feed.URL));
}
/// <summary>
/// Constructor
/// </summary>
/// <param name="title">Title of the item</param>
/// <param name="text">Summary of the item</param>
/// <param name="url">URL of the item</param>
/// <param name="date">Datestamp of the item</param>
/// <param name="feed">Feed information</param>
/// <param name="image">Image associated with the item</param>
public RSSItem(String title, String text, String url, DateTimeOffset date, RSSFeed feed, string image)
{
Title = title;
Text = text;
Url = url;
Datestamp = date;
Feed = feed;
Image = image;
}
/// <summary>
/// Constructor
/// </summary>
/// <param name="title">Title of the item</param>
/// <param name="text">Summary of the item</param>
/// <param name="url">URL of the item</param>
/// <param name="date">Datestamp of the item</param>
/// <param name="feed">Feed information</param>
/// <param name="image">Image associated with the item</param>
public RSSItem(String title, String text, String url, DateTimeOffset date, RSSFeed feed, string image)
{
Title = title;
Text = text;
Url = url;
Datestamp = date;
Feed = feed;
Image = image;
}
/// <summary>
/// Returns a RSS feed from cache based on page id and feed id
/// </summary>
/// <param name="pageId">Id of the page where the feed resides</param>
/// <param name="feedId">Id of the feed</param>
/// <returns>RSS feed</returns>
public static RSSFeed GetRSSFeed(int pageId, int feedId)
{
RSSFeed feed = null;
int count = 0;
foreach (RSSFeed f in CachedItems.Cache[pageId].Feeds)
{
if (!f.IsVisible)
{
continue;
}
else
{
if (count == feedId)
{
feed = f;
break;
}
count++;
}
}
return(feed);
}
/// <summary>
/// Method for retrieving RSS feed information, especially the image of the feed
/// </summary>
/// <param name="feed">Feed whose information to fetch</param>
/// <param name="onGetRSSFeedImageUriCompleted">Action to take when information has been retrieved</param>
/// <param name="onError">Action to take when an error occurs</param>
public static void GetRSSFeedImageUri(RSSFeed feed, Action<Uri, RSSFeed> onGetRSSFeedImageUriCompleted = null, Action<Exception> onError = null)
{
WebClient webClient = new WebClient();
webClient.OpenReadCompleted += delegate(object sender, OpenReadCompletedEventArgs e)
{
try
{
if (e.Error != null)
{
if (onError != null)
{
onError(e.Error);
}
return;
}
XmlReader response = XmlReader.Create(e.Result);
SyndicationFeed rssFeed = SyndicationFeed.Load(response);
if (onGetRSSFeedImageUriCompleted != null)
{
onGetRSSFeedImageUriCompleted(rssFeed.ImageUrl, feed);
}
}
catch (Exception error)
{
if (onError != null)
{
onError(error);
}
}
};
webClient.OpenReadAsync(new Uri(feed.URL));
}
/// <summary>
/// Method that initializes a single pivot item
/// </summary>
/// <param name="f">Feed to initialize the pivot item from</param>
private void CreatePivotItem(RSSFeed f)
{
if (f.IsVisible)
{
// Programmatically create the pivot item
// Note that most of the time you'd want to do this with XAML and data binding,
// or at least use a data template for the content of the pivot item. However in
// this case it's better to create everything manually because we are updating the state
// of pivot items in LoadItems(). This means that we have to access the pivot
// item controls directly, which is very difficult to do in Silverlight if the
// controls are being created through data template (this is because FindName()
// method of FrameworkTemplate is not available in Silverlight). It would probably be
// possible to go around the need of accessing controls directly through data-binding but
// that would most likely lead to more code lines than the 16 we need here.
PivotItem pivotItem = new PivotItem();
pivotItem.Header = f.Title;
pivotItem.Margin = new Thickness(0, 0, 0, 0);
Grid grid = new Grid();
grid.Margin = new Thickness(25, 0, 0, 0);
// Add a progressbar for each pivot item, initially hidden
ProgressBar progressBar = new ProgressBar();
progressBar.IsIndeterminate = false;
progressBar.Visibility = Visibility.Collapsed;
grid.Children.Add(progressBar);
ListBox listBox = new ListBox();
listBox.ItemTemplate = (DataTemplate)Resources["RSSItemTemplate"];
listBox.SelectionChanged += ItemSelectionChanged;
// Enable tilt effect for the listbox.
// TilEffect is part of Silverlight Toolkit which does not ship as part of this example. Please see
// release notes for instructions how to install and use Silverlight Toolkit.
TiltEffect.SetIsTiltEnabled(listBox, true);
grid.Children.Add(listBox);
pivotItem.Content = grid;
RSSItemsPivot.Items.Add(pivotItem);
}
}
/// <summary>
/// Gets the RSS items
/// </summary>
/// <param name="feed">The RSS feed</param>
/// <param name="onGetRSSItemsCompleted">Callback on complete</param>
/// <param name="onError">Callback for errors</param>
public static void GetRSSItems(int pageId, int feedId, bool useCache, Action <IEnumerable <RSSItem> > onGetRSSItemsCompleted = null, Action <Exception> onError = null)
{
DateTime validUntilThis = DateTime.Now;
validUntilThis = validUntilThis.AddMinutes(-EXPIRE_TIME);
RSSFeed feed = GetRSSFeed(pageId, feedId);
bool feedExists = (feed != null);
bool feedHasItems = (feedExists && feed.Items != null && feed.Items.Count > 0);
bool cacheHasExpired = (DateTime.Compare(validUntilThis, feed.Timestamp) > 0);
// First check if this valid items for this feed exist in the cache already
if (feedExists &&
feedHasItems &&
useCache &&
!cacheHasExpired &&
onGetRSSItemsCompleted != null)
{
onGetRSSItemsCompleted(feed.Items);
}
// Items not found in cache, perform a web request
else
{
WebClient webClient = new WebClient();
webClient.OpenReadCompleted += delegate(object sender, OpenReadCompletedEventArgs e)
{
try
{
if (e.Error != null)
{
if (onError != null)
{
onError(e.Error);
}
return;
}
List <RSSItem> rssItems = new List <RSSItem>();
XmlReader response = XmlReader.Create(e.Result);
SyndicationFeed rssFeed = SyndicationFeed.Load(response);
foreach (SyndicationItem syndicationItem in rssFeed.Items)
{
// Clean the title in case it includes line breaks
string title = syndicationItem.Title.Text;
title = title.Replace("\r\n", "\n").Replace("\r", "\n").Replace("\n", " ");
// Check for "enclosure" tag that references an image
string image = "";
foreach (SyndicationLink link in syndicationItem.Links)
{
if (link.RelationshipType == "enclosure" &&
link.MediaType.StartsWith("image/"))
{
image = link.Uri.ToString();
break;
}
}
RSSItem rssItem = new RSSItem(
title,
syndicationItem.Summary.Text,
syndicationItem.Links[0].Uri.AbsoluteUri,
syndicationItem.PublishDate,
feed,
image);
rssItems.Add(rssItem);
}
// Cache the results
feed.Items = rssItems;
feed.Timestamp = DateTime.Now;
// Call the callback with the list of RSSItems
if (onGetRSSItemsCompleted != null)
{
onGetRSSItemsCompleted(rssItems);
}
}
catch (Exception error)
{
if (onError != null)
{
onError(error);
}
}
};
webClient.OpenReadAsync(new Uri(feed.URL));
}
}
