private async void Mource_Move(object sender, RoutedEventArgs e)        {            StackPanel panel = (StackPanel)sender;            TextBlock block = (TextBlock)panel.Children[1];            string message = block.Text;            var root = Windows.Storage.ApplicationData.Current.LocalFolder;            var path = await root.CreateFolderAsync("fillf", CreationCollisionOption.OpenIfExists);            var filename = await path.CreateFileAsync("aaa.txt", CreationCollisionOption.OpenIfExists);            var _WriteThis = message;            await Windows.Storage.FileIO.AppendTextAsync(filename, _WriteThis);            //检验是否写入成功            var _ReadThis = await Windows.Storage.FileIO.ReadTextAsync(filename);            MessageDialog dialog = new MessageDialog(_ReadThis);            dialog.ShowAsync();        }