FrameworkExtentionMethods.cs (3,525 bytes)   

public static void Unblur(this FrameworkElement frameworkElement, FrameworkElement parent, TimeSpan duration, Action completed = null)
        {
            if (!(frameworkElement.Effect is BlurEffect blurEffect))
                return;

            string key = "Blur" + frameworkElement.GetHashCode();

            if (frameworkElement.Tag is StoryboardTag tag)
            {
                tag.Item1.Stop();
                parent.Resources.Remove(key);
            }

            float from = blurEffect.Radius;

            DoubleAnimation animation = new DoubleAnimation();
            animation.Duration = new Duration(duration);
            animation.AutoReverse = false;
            animation.FillBehavior = FillBehavior.Stop;

            Storyboard storyboard = new Storyboard();
            storyboard.AutoReverse = false;
            storyboard.Duration = animation.Duration;
            storyboard.FillBehavior = FillBehavior.Stop;
            storyboard.Children.Add(animation);

            parent.Resources.Add(key, storyboard);
            frameworkElement.Tag = new StoryboardTag(storyboard, 1);

            Storyboard.SetTarget(animation, frameworkElement);
            Storyboard.SetTargetProperty(animation, new PropertyPath("Effect.Radius"));
            animation.From = from;
            animation.To = 0;
            storyboard.Completed += (sender2, e2) =>
            {
                parent.Resources.Remove(key);
                frameworkElement.Tag = null;
                blurEffect.Radius = 0;
                frameworkElement.Effect = null;
                completed?.Invoke();
            };

            storyboard.Begin();
        }

        public static void Blur(this FrameworkElement frameworkElement, FrameworkElement parent, float radius, TimeSpan duration, Action completed = null)
        {
            if (!(frameworkElement.Effect is BlurEffect blurEffect))
            {
                blurEffect = new BlurEffect();
                frameworkElement.Effect = blurEffect;
            }

            string key = "Blur" + frameworkElement.GetHashCode();

            if (frameworkElement.Tag is StoryboardTag tag)
            {
                tag.Item1.Stop();
                parent.Resources.Remove(key);
            }

            float from = blurEffect.Radius;

            DoubleAnimation animation = new DoubleAnimation();
            animation.Duration = new Duration(duration);
            animation.AutoReverse = false;
            animation.FillBehavior = FillBehavior.Stop;

            Storyboard storyboard = new Storyboard();
            storyboard.AutoReverse = false;
            storyboard.Duration = animation.Duration;
            storyboard.FillBehavior = FillBehavior.Stop;
            storyboard.Children.Add(animation);

            parent.Resources.Add(key, storyboard);
            frameworkElement.Tag = new StoryboardTag(storyboard, 1);

            Storyboard.SetTarget(animation, frameworkElement);
            Storyboard.SetTargetProperty(animation, new PropertyPath("Effect.Radius"));
            animation.From = from;
            animation.To = radius;
            storyboard.Completed += (sender2, e2) =>
            {
                parent.Resources.Remove(key);
                frameworkElement.Tag = null;
                blurEffect.Radius = radius;
                completed?.Invoke();
            };

            storyboard.Begin();
        }