WP 8.1 - 如果知道图像是 URL，如何将图像保存到独立存储

我有图像网址。

如何将其保存到WP 8.1中的独立存储中。

我可以触发保存它，然后只用一个按钮分享到Facebook吗？

这是我的代码 - 遵循Burak Kaan Köse的代码可以很好地工作：

public async void GetImage()
    {
        StorageFolder folder = ApplicationData.Current.LocalFolder;
            if (folder != null)
            {
                StorageFile file = await folder.CreateFileAsync("imagefile", CreationCollisionOption.ReplaceExisting);
                string url = imgUri[fLFl.SelectedIndex].ToString();
                HttpClient client = new HttpClient();
                byte[] fileContent = await client.GetByteArrayAsync(url); ; // This is where you set your content as byteArray
                Stream fileStream = await file.OpenStreamForWriteAsync();
                fileStream.Write(fileContent, 0, fileContent.Length);
                fileStream.Flush();
                fileStream.Dispose();
            }
    }

private async void SaveFile()
{
    try
    {
        StorageFolder folder = ApplicationData.Current.LocalFolder;
        if(folder != null)
        {
            StorageFile file = await folder.CreateFileAsync("imagefile", CreationCollisionOption.ReplaceExisting);
            byte[] fileContnet = null; // This is where you set your content as byteArray
            Stream fileStream = await file.OpenStreamForWriteAsync();
            fileStream.Write(fileContent, 0, fileContent.Length);
            fileStream.Flush();
            fileStream.Close();
        }
    }
    catch (Exception ex)
    {
        // Some Exception handling code
    }
}