异步方法C＃中的UWP进度条

Question

I am developing application where I am processing images. Image processing take sometime (for about 10 seconds). I want to add a progress bar to complete unless image processing in done. I have this progress bar in xaml

<ProgressBar Width="200"                               
Foreground="#FF8B64C3"
Value="20" 
Maximum="100" 
BorderBrush="#FF411F72" 
BorderThickness="1"/>

This is the event that is called when button is clicked for image processing

private void ProcessImageButton_Click(object sender, RoutedEventArgs e)
{          
    applyFilters(image1Pixels, image1Width, image1Height);          
}

I want to start progress bar when this ProcessImageButton button is clicked. This is the applyFilters method.

 private async void applyFilters(byte[] pixels, uint width, uint height)
 {
        ProcessImage processImage = new ProcessImage(pixels, width, height);

        byte[] effect = processImage.applyEffect(width, height);

        WriteableBitmap result_image = new WriteableBitmap((int)width, (int)height);
        using (Stream stream = result_image .PixelBuffer.AsStream())
        {
            await stream.WriteAsync(effect, 0, effect.Length);
            MainImage.Source = result_image ;
        }
 }

I want my progress bar to complete before storing result_image into MainImage.Source.

Answer 1

you can use a indeterminate progress bar

<ProgressBar x:Name="ImageProgressBar" Visibility="Collapsed" IsIndeterminate="true"/>

and you need to change the visibility before and after the image is loaded

        ImageProgressBar.Visibility = Visibility.Visible;

        ImageProgressBar.Visibility = Visibility.Collapsed;

Answer 2

You can use a <ProgressRing x:Name="progress" Height="50" Width="50" IsActive="False" />

and set progress.IsActive = true; in the beginning of the operation and

progress.IsActive = false;

at the end of the operation