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

如何将图像保存到Windows Phone 8.1 RT中的“已保存的图片”文件夹？ 我使用HttpClient从网上下载了图像。

Answer 1

你只需要这个

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);

您需要在清单中设置图片库功能。

Answer 2

感谢MSDN论坛上的mSpot Inc，我解决了这个问题。 我现在使用的代码：

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

如果您希望用户选择文件位置，您需要使用带有pictureLibrary的FileSavePicker作为SuggestedStartLocation 。

如果您想在没有用户选择目的地的情况下保存它，您需要使用以下内容：

Windows.Storage.KnownFolders.picturesLibrary.createFileAsync

我相信在这两种情况下，您都需要在清单中设置Pictures Library 功能 。

Answer 4

目前，我使用这个原生实现：

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);