/// <summary>
/// This function sets up the background request for the image
/// </summary>
/// <param name="index"></param>
protected override void OnRequestSlowData(int index)
{
//if this request has already been made once
if (_pendingItemRequest.ContainsKey(index))
{
//cancel the request
return;
}
//If this virtual list does not have a proper query
if (Query == "")
{
//don't try to get an image
return;
}
//add this index to the pendingItemRequest list so that we know this has already been requested
_pendingItemRequest[index] = index;
//create a new slowdata Request item.
SlowDataItem slowData = new SlowDataItem();
//set the slowdata index to match index requested
slowData.Index = index;
//Read the path of the image url from the relevant video item.
slowData.PicturePath = ((VideoItem)this[slowData.Index]).Format.CoverArtLargeUri;
//schedule this process to run on a worker thread
Microsoft.MediaCenter.UI.Application.DeferredInvokeOnWorkerThread(GetVideoImage, ProcessSlowData, slowData);
}
/// <summary>
/// This function goes and gets the image
/// </summary>
/// <param name="args"></param>
private static void GetVideoImage(object args)
{
// Heavy operation: get video information from amazon.
ThreadPriority priority = Thread.CurrentThread.Priority;
try
{
Thread.CurrentThread.Priority = ThreadPriority.Lowest;
SlowDataItem slowData = (SlowDataItem)args;
if (slowData.PicturePath == "")
{
return;
}
try
{
//actually go and get the image.
slowData.TitleImage = new Image(slowData.PicturePath);
}
catch (Exception e)
{
//not sure what we can do in this case
}
}
finally
{
Thread.CurrentThread.Priority = priority;
}
}
/// <summary>
/// This function updates the relevant video item with the retrieved image.
/// </summary>
/// <param name="args"></param>
private void ProcessSlowData(object args)
{
SlowDataItem slowData = (SlowDataItem)args;
_pendingItemRequest.Remove(slowData.Index);
if (IsDisposed || !IsItemAvailable(slowData.Index))
{
return;
}
//go and get the relevant video item
VideoItem v = (VideoItem)this[slowData.Index];
//set the image to be the retrieved image
v.Image = slowData.TitleImage;
}
