private void DownloadSelectedPictures(List <Picture> toProcess)
{
//validate that there are actually pictures to be processed (search may return 0 results, or very few results)
if (toProcess.Count > 0)
{
//download the new pictures, wait for them to all finish
ManualResetEvent[] manualEvents = new ManualResetEvent[toProcess.Count];
// Queue the work items that create and write to the files.
for (int i = 0; i < toProcess.Count; i++)
{
manualEvents[i] = new ManualResetEvent(false);
ThreadPool.QueueUserWorkItem(new WaitCallback(delegate(object state)
{
object[] states = (object[])state;
ManualResetEvent mre = (ManualResetEvent)states[0];
Picture p = (Picture)states[1];
PictureDownload pd = DownloadManager.Current.GetPicture(p, false);
//hook events and set mre in event
PictureDownload.PictureDownloadEvent pdEvent = new PictureDownload.PictureDownloadEvent(
delegate(PictureDownload t)
{
mre.Set();
});
//on success or failure make sure to set mre
pd.PictureDownloaded += pdEvent;
pd.PictureDownloadingAborted += pdEvent;
DownloadManager.Current.QueuePicture(pd);
}), new object[] { manualEvents[i], toProcess[i] });
}
//wait for all items to finish
//3 minute timeout
WaitHandle.WaitAll(manualEvents, 3 * 60 * 1000);
CurrentPictures.AddRange(toProcess);
}
}
public List <Picture> GetPictures(int count)
{
lock (CurrentPictures)
{
//calculate how many pictures we need to get download
int toDownloadCount = count - CurrentPictures.Count;
if (toDownloadCount > 0)
{
Random random = new Random();
var allPics = (from c in AllPictures select c.Pictures)
.SelectMany(p => p)
.Where(p => !(CurrentPictures.Contains(p)))
.OrderBy(p => random.Next());
List <Picture> toProcess = allPics.Take(count).ToList();
DownloadSelectedPictures(toProcess);
}
return(CurrentPictures.Take(count).ToList());
}
}
