public sealed partial class MainPage : Page
    {
        List _fruits;
        public MainPage()
        {
            this.InitializeComponent();
        }
        public List Data
        {
            get
            {
                if (_fruits == null)
                {
                    _fruits = DataCreator.CreateFruit();
                }

                return _fruits;
            }
        }
        private async void Button_Click_1(object sender, RoutedEventArgs e)
        {
            var picker = new FileSavePicker();
            Enum.GetNames(typeof(ImageFormat)).ToList().ForEach(fmt =>
            {
                picker.FileTypeChoices.Add(fmt.ToString().ToUpper(), new List<string>() { "." + fmt.ToString().ToLower() });
            });
            StorageFile file = await picker.PickSaveFileAsync();
            if (file != null)
            {
                Stream stream = new MemoryStream();
                var extension = file.FileType.Substring(1, file.FileType.Length - 1);
                ImageFormat fmt = (ImageFormat)Enum.Parse(typeof(ImageFormat), extension, true);
                flexChart.SaveImage(stream, fmt);
                using (Stream saveStream = await file.OpenStreamForWriteAsync())
                {
                    stream.CopyTo(saveStream);
                    stream.Seek(0, SeekOrigin.Begin);
                    saveStream.Seek(0, SeekOrigin.Begin);
                    saveStream.Flush();
                    saveStream.Dispose();
                }
            }
        }
    }