Question

I have a WPF application that will set an image source when a button is clicked
I want to then clear the image source after so many seconds, say 15 seconds have passed.
How can I do this?
I have tried to use Thread.sleep but it clears the source right away then just pauses the application for the 15 seconds

here is what i have for that method

 private void btnCapture_Click(object sender, RoutedEventArgs e)
 {  
    imgCapture.Source = //my image source;

    Thread.Sleep(15000);
    imgCapture.Source = null;

 }

I have also tried

 private void btnCapture_Click(object sender, RoutedEventArgs e)
  {  
    imgCapture.Source = //my image source;


    imgCapture.Source = null;
     Thread thread = new Thread(new ThreadStart(clearSource));
        thread.Start();

  }

    private void clearSource()
    {
        Thread.Sleep(15000);
        imgCapture.Source = null;
    }

but I get an error saying The calling thread cannot access this object because a different thread owns it.
How can I get that image source to clear after 15 seconds.
Thanks!

Answer 1

Use a DispatcherTimer:

DispatcherTimer timer = new DispatcherTimer { Interval = TimeSpan.FromSeconds(15) };

    // in constructor
    timer.Tick += OnTimerTick;

private void btnCapture_Click(object sender, RoutedEventArgs e)
{
    imgCapture.Source = //my image source;
    timer.Start();
}

private void OnTimerTick(object sender, EventArgs e)
{
    timer.Stop();
    imgCapture.Source = null;
}