我使用下面的代码来下载/保存图像并在以后打开它,但是在以后的OpenAsync中,它会引发UnauthorizedAccessException,看起来该文件不是关闭的,但实际上IRandomAccessStream/DataWriter具有被处置。StorageFile.OpenAsync中的UnauthorizedAccessException
HttpClient httpClient = new HttpClient();
HttpRequestMessage request = new HttpRequestMessage(HttpMethod.Get, "http://www.silverlightshow.net/Storage/Users/nikolayraychev/Perspective_Transforms_4.gif");
HttpResponseMessage response = await httpClient.SendAsync(request, HttpCompletionOption.ResponseHeadersRead);
//Write Image File
StorageFile imageFile = await ApplicationData.Current.LocalFolder.CreateFileAsync("test.gif", CreationCollisionOption.ReplaceExisting);
using (IRandomAccessStream fs = await imageFile.OpenAsync(FileAccessMode.ReadWrite))
{
using (DataWriter writer = new DataWriter(fs.GetOutputStreamAt(0)))
{
writer.WriteBytes(await response.Content.ReadAsByteArrayAsync());
await writer.StoreAsync();
writer.DetachStream();
await fs.FlushAsync();
}
}
StorageFile imageFile1 = await ApplicationData.Current.LocalFolder.GetFileAsync("test.gif");
//Exception is throwed here
using (IRandomAccessStream stream = await imageFile1.OpenAsync(FileAccessMode.Read))
{
BitmapImage img = new BitmapImage();
img.SetSource(stream);
}
你不需要刷新任何作家或流。他们在Dispose上冲洗。他们为什么会丢掉你的数据? – usr
等待fs.FlushAsync()只是确保异步刷新操作完成。 – Yanzhi