xamarin.ios应用程序中的进度指示器

Question

我是Xamarin的初学者并且有问题。我必须从微调器进度条更改为常规进度条，例如this

我在MainPage.xaml中有这个故事板

<Storyboard x:Name="SpinnerStoryboard">
            <DoubleAnimation FillBehavior="HoldEnd"
                             RepeatBehavior="Forever"
                             Storyboard.TargetName="SpinnerTransform"
                             Storyboard.TargetProperty="Angle"
                             From="0"
                             To="360"
                             Duration="00:00:00.5" />
        </Storyboard>

同样在MainPage.xaml.cs中：

 private void RefreshableScrollableContentPresenter_OnPullProgressChanged(object sender, RefreshProgressEventArgs e)
        {
            if (e.IsRefreshable)
            {
                if (e.PullProgress == 1)
                {
                    // Progress = 1.0 means that the refresh has been triggered.
                    if (SpinnerStoryboard.GetCurrentState() == ClockState.Stopped)
                        SpinnerStoryboard.Begin();
                }
                else if (SpinnerStoryboard.GetCurrentState() != ClockState.Stopped)
                    SpinnerStoryboard.Stop();
                else
                {
                    // Turn the indicator by an amount proportional to the pull progress.
                    SpinnerTransform.Angle = e.PullProgress * 360;
                }
            }
        }

和

private void RefreshableScrollableContentPresenter_OnRefreshRequested(object sender, RefreshRequestedEventArgs e)
        {
            var presenter = sender as RefreshableScrollableContentPresenter;
            if (presenter != null)
            {
                using (var deferral = presenter.AutoRefresh ? e.GetDeferral() : null)
                {
                    mainPageViewModel.ProductsViewModel.GetProductsCommand.Execute();

                    if (SpinnerStoryboard.GetCurrentState() != ClockState.Stopped)
                        SpinnerStoryboard.Stop();
                }
            }
        }