Question

我正在使用Unsplash API来获取图像。当我发送图片请求时，答案的一部分是图片网址，如下所示：

https://images.unsplash.com/photo-1535159530326-d7bf54bfb24e?ixlib=rb-0.3.5&q=85&fm=jpg&crop=entropy&cs=srgb&ixid=eyJhcHBfaWQiOjM1NDkzfQ&s

我能够将此URL设置为BitmapImage，并使其在应用程序UI中成为Image Source。但是我无法下载该文件以使其成为StorageFile。

如何从此类URL下载图像和/或将其设置为StorageFile？

Answer 1

以下代码会将文件下载到本地存储中，然后为您提供一个Uri，可用于设置图像源：

    private async Task<String> DownloadImage(string url, String fileName)
    {
        const String imagesSubdirectory = "DownloadedImages";
        var rootFolder = await ApplicationData.Current.LocalFolder.CreateFolderAsync(imagesSubdirectory, CreationCollisionOption.OpenIfExists);

        var storageFile = await rootFolder.CreateFileAsync(fileName, CreationCollisionOption.ReplaceExisting);

        using (HttpClient client = new HttpClient())
        {
            byte[] buffer = await client.GetByteArrayAsync(url);
            using (Stream stream = await storageFile.OpenStreamForWriteAsync())
                stream.Write(buffer, 0, buffer.Length);
        }

        // Use this path to load image
        String newPath = String.Format("ms-appdata:///local/{0}/{1}", imagesSubdirectory, fileName);

        return newPath;
    }

    // Here is an example of how to use the new DownloadImage() method
    private async void Button_Download(object sender, RoutedEventArgs e)
    {
        var uniqueFileName = $@"{Guid.NewGuid()}.jpg";

        String newPath = await DownloadImage("https://images.unsplash.com/photo-1535159530326-d7bf54bfb24e?ixlib=rb-0.3.5&q=85&fm=jpg&crop=entropy&cs=srgb&ixid=eyJhcHBfaWQiOjM1NDkzfQ&s=6dbf8e03a25f469d0f845992e6b2eb9e",
            uniqueFileName);
        myImage.Source = new BitmapImage(new Uri(newPath));
    }

如何将图像URL转换为StorageFile？

1 个答案: