private async Task LoadTileImageAsync(Tile tile, Uri uri, string cacheKey)
{
var cacheItem = await Cache.GetAsync(cacheKey);
var cacheBuffer = cacheItem?.Buffer;
var loaded = false;
if (cacheBuffer == null || cacheItem.Expiration < DateTime.UtcNow)
{
try
{
loaded = await ImageLoader.LoadHttpTileImageAsync(uri, async (buffer, maxAge) =>
{
await SetTileImageAsync(tile, buffer); // create BitmapImage before caching
await Cache.SetAsync(cacheKey, buffer, GetExpiration(maxAge));
});
}
catch (Exception ex)
{
Debug.WriteLine("TileImageLoader: {0}: {1}", uri, ex.Message);
}
}
if (!loaded && cacheBuffer != null) // keep expired image if download failed
{
await SetTileImageAsync(tile, cacheBuffer);
}
}
private async Task LoadTileImageAsync(Tile tile, Uri uri, string cacheKey)
{
DateTime expiration;
var buffer = GetCachedImage(cacheKey, out expiration);
var loaded = false;
if (buffer == null || expiration < DateTime.UtcNow)
{
try
{
loaded = await ImageLoader.LoadHttpTileImageAsync(uri, async (stream, maxAge) =>
{
await SetTileImageAsync(tile, stream); // create BitmapFrame before caching
SetCachedImage(cacheKey, stream, GetExpiration(maxAge));
});
}
catch (Exception ex)
{
Debug.WriteLine("TileImageLoader: {0}: {1}", uri, ex.Message);
}
}
if (!loaded && buffer != null) // keep expired image if download failed
{
using (var stream = new MemoryStream(buffer))
{
await SetTileImageAsync(tile, stream);
}
}
}
