将图像从Web保存到Windows Phone 8.1 RT C＃中的“保存的图片”文件夹

Question

How can I save an image to the Saved Pictures folder in Windows Phone 8.1 RT? I downloaded the image from the web using HttpClient.

Answer 1

You just need this

var url = "Some URL";
var fileName = Path.GetFileName(url.LocalPath);
var thumbnail = RandomAccessStreamReference.CreateFromUri(url);

var remoteFile = await StorageFile.CreateStreamedFileFromUriAsync(fileName, url, thumbnail);
await remoteFile.CopyAsync(KnownFolders.SavedPictures, fileName, NameCollisionOption.GenerateUniqueName);

You need to set the Pictures Library capability in your manifest.

Answer 2

I solved it thanks to mSpot Inc on the MSDN-forums. The code I use now:

StorageFolder picsFolder = KnownFolders.SavedPictures;
StorageFile file = await picsFolder.CreateFileAsync("myImage.jpg", CreationCollisionOption.GenerateUniqueName);

string url = "http://somewebsite.com/someimage.jpg";
HttpClient client = new HttpClient();

byte[] responseBytes = await client.GetByteArrayAsync(url);

var stream = await file.OpenAsync(FileAccessMode.ReadWrite);

using (var outputStream = stream.GetOutputStreamAt(0))
{
    DataWriter writer = new DataWriter(outputStream);
    writer.WriteBytes(responseBytes);
    writer.StoreAsync();
    outputStream.FlushAsync();
}

Answer 3

If you want the user to pick for the file location you need to use the FileSavePicker with pictureLibrary as the SuggestedStartLocation .

If you want to save it without the user to select the destination you need to use something like this:

Windows.Storage.KnownFolders.picturesLibrary.createFileAsync

I believe in both cases you need to set the Pictures Library capability in your manifest.

Answer 4

At the moment, I use this native implementation:

var url = new Uri(UriString, UriKind.Absolute);
var fileName = Path.GetFileName(url.LocalPath);

var w = WebRequest.CreateHttp(url);
var response = await Task.Factory.FromAsync<WebResponse>(w.BeginGetResponse, w.EndGetResponse, null);
await response.GetResponseStream().CopyToAsync(new FileStream(ApplicationData.Current.LocalFolder.Path + @"\" + fileName, FileMode.CreateNew));
var file = await ApplicationData.Current.LocalFolder.GetFileAsync(fileName);
await file.CopyAsync(KnownFolders.SavedPictures, fileName, NameCollisionOption.FailIfExists);