Windows phone 8 保存图片后的进度条可见性

我可以在将am图像保存到媒体库时显示进度指示器，但我不知道如何在保存图片后更改

IsVisible=false

。以下是我使用的代码-

async void Save_Click(object sender, EventArgs e)
    {
        ProgressIndicator progress = new ProgressIndicator();
        progress.IsVisible = true;
        progress.IsIndeterminate = true;
        progress.Text = "saving image...";

        //Save a copy of the image
        using (MediaLibrary library = new MediaLibrary())
        {
            var imgStream = (await App.CurrPhoto.RawSession.RenderToJpegAsync()).AsStream();
            library.SavePicture(DateTime.UtcNow.Ticks.ToString(), imgStream);
        }

        SystemTray.SetProgressIndicator(this, progress);
    }

---

在执行操作前设置

ProgressIndicator

，然后在保存代码后禁用它

ProgressIndicator progress = new ProgressIndicator();
progress.IsVisible = true;
progress.IsIndeterminate = true;
progress.Text = "saving image...";

//set the indicator before the save code
SystemTray.SetProgressIndicator(this, progress);

//Save a copy of the image
using (MediaLibrary library = new MediaLibrary())
{
   var imgStream = (await App.CurrPhoto.RawSession.RenderToJpegAsync()).AsStream();
   library.SavePicture(DateTime.UtcNow.Ticks.ToString(), imgStream);
}

//disable it
SystemTray.SetProgressIndicator(this, null);