static async ValueTask <ImageSource> FetchImageAsync(Uri url)
{
var data = await Reddit.FetchImageAsync(url);
return(new StreamImageSource
{
Stream = _ => Task.FromResult((Stream) new MemoryStream(data))
});
}
static async ValueTask <ImageSource?> FetchImageAsync(Uri url)
{
var raStream = new InMemoryRandomAccessStream();
await raStream.WriteAsync((await Reddit.FetchImageAsync(url)).AsBuffer());
raStream.Seek(0);
var bitmap = new BitmapImage();
await bitmap.SetSourceAsync(raStream);
return(bitmap);
}
public MainWindowViewModel()
{
this.Items = new ObservableCollection <ItemViewModel>();
this.IndicatorPile = PileFactory.Create <Panel>();
// A handler for window loaded
this.Ready = Command.Factory.CreateSync(() =>
{
this.IsEnabled = true;
});
// A handler for fetch button
this.Fetch = CommandFactory.Create(async() =>
{
// Disable button
this.IsEnabled = false;
// Temporary rent Grid children accessor
await this.IndicatorPile.RentAsync(async indicator =>
{
// Show WaitingBlock control
var waitingBlock = new WaitingBlock();
indicator.Children.Add(waitingBlock);
try
{
// Uses Reddit API
var reddits = await Reddit.FetchNewPostsAsync("r/aww");
this.Items.Clear();
static async ValueTask <ImageSource?> FetchImageAsync(Uri url)
{
try
{
var bitmap = new WriteableBitmap(
BitmapFrame.Create(new MemoryStream(await Reddit.FetchImageAsync(url))));
bitmap.Freeze();
return(bitmap);
}
// Some images will cause decoding error by WPF's BitmapFrame, so ignoring it.
catch (FileFormatException)
{
return(null);
}
}
foreach (var reddit in reddits)
{
this.Items.Add(new ItemViewModel
{
Title = reddit.Title,
Score = reddit.Score,
Image = await FetchImageAsync(reddit.Url)
});
}
}
static async ValueTask <ImageSource?> FetchImageAsync(Uri url)
{
try
{
var bitmap = new WriteableBitmap(
BitmapFrame.Create(new MemoryStream(await Reddit.FetchImageAsync(url))));
bitmap.Freeze();
return(bitmap);
}
// Some images will cause decoding error by WPF's BitmapFrame, so ignoring it.
catch (FileFormatException)
{
return(null);
}
}
private async void fetchButton_Click(object sender, EventArgs e)
{
this.Enabled = false;
try
{
// Uses Reddit API
var reddits = await Reddit.FetchNewPostsAsync("r/aww");
this.itemsList.Items.Clear();
this.imageList.Images.Clear();
foreach (var reddit in reddits)
{
this.imageList.Images.Add(await Reddit.FetchImageAsync(reddit.Url));
this.itemsList.Items.Add(reddit.Title, this.imageList.Images.Count - 1);
}
}
finally
{
this.Enabled = true;
}
}
static async ValueTask <Bitmap?> FetchImageAsync(Uri url) => new Bitmap(new MemoryStream(await Reddit.FetchImageAsync(url)));
static async ValueTask <ImageSource?> FetchImageAsync(Uri url)
{
var bitmap = new BitmapImage();
bitmap.SetSource(new MemoryStream(await Reddit.FetchImageAsync(url)));
return(bitmap);
}