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public static CopyFromBytes ( byte bytes ) : |
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| bytes | byte | 読み込む対象となるバイト列 |
| return | ||
/// <summary>
/// 指定された URL にある画像を非同期に取得するメソッド
/// </summary>
/// <param name="address">取得先の URL</param>
/// <param name="force">キャッシュを使用せずに取得する場合は true</param>
/// <returns>非同期に画像を取得するタスク</returns>
public Task <MemoryImage> DownloadImageAsync(string address, bool force = false)
{
var cancelToken = this.cancelTokenSource.Token;
return(Task.Factory.StartNew(() =>
{
Task <MemoryImage> cachedImageTask = null;
lock (this.lockObject)
{
if (force)
{
this.innerDictionary.Remove(address);
}
if (this.innerDictionary.ContainsKey(address) && !this.innerDictionary[address].IsFaulted)
{
cachedImageTask = this.innerDictionary[address];
}
}
if (cachedImageTask != null)
{
return cachedImageTask;
}
cancelToken.ThrowIfCancellationRequested();
using (var client = new OTWebClient()
{
Timeout = 10000
})
{
var imageTask = client.DownloadDataAsync(new Uri(address), cancelToken).ContinueWith(t =>
{
MemoryImage image = null;
if (t.Status == TaskStatus.RanToCompletion)
{
image = MemoryImage.CopyFromBytes(t.Result);
}
if (t.Exception != null)
{
t.Exception.Handle(e => e is WebException);
}
// FIXME: MemoryImage.Dispose() が正しいタイミングで呼ばれるように修正すべき
return image;
}, cancelToken);
lock (this.lockObject)
{
this.innerDictionary[address] = imageTask;
}
return imageTask;
}
}, cancelToken).Unwrap());
}
public new Task LoadAsync(string url)
{
this._ImageLocation = url;
if (this.loadAsyncTask != null && !this.loadAsyncTask.IsCompleted)
{
this.CancelAsync();
}
this.Image = base.InitialImage;
Uri uri;
try
{
uri = new Uri(url);
}
catch (UriFormatException)
{
uri = new Uri(Path.GetFullPath(url));
}
var client = new OTWebClient();
client.DownloadProgressChanged += (s, e) =>
{
this.OnLoadProgressChanged(new ProgressChangedEventArgs(e.ProgressPercentage, e.UserState));
};
this.loadAsyncCancelTokenSource = new CancellationTokenSource();
var cancelToken = this.loadAsyncCancelTokenSource.Token;
var loadImageTask = client.DownloadDataAsync(uri, cancelToken);
// UnobservedTaskException イベントを発生させないようにする
loadImageTask.ContinueWith(t => { var ignore = t.Exception; }, TaskContinuationOptions.OnlyOnFaulted);
var uiScheduler = TaskScheduler.FromCurrentSynchronizationContext();
return(loadImageTask.ContinueWith(t => {
client.Dispose();
if (t.IsFaulted)
{
throw t.Exception;
}
return MemoryImage.CopyFromBytes(t.Result);
}, cancelToken)
.ContinueWith(t =>
{
if (!t.IsCanceled)
{
if (t.IsFaulted)
{
this.Image = base.ErrorImage;
}
else
{
this.Image = t.Result.Image;
this.memoryImage = t.Result;
}
}
var exp = t.Exception != null ? t.Exception.Flatten() : null;
this.OnLoadCompleted(new AsyncCompletedEventArgs(exp, t.IsCanceled, null));
}, uiScheduler));
}
