Как заставить элемент позиционироваться мгновенно

border1.Margin = new Thickness(12, i, 0, 0);
System.Threading.Thread.Sleep(1000);
border1.Margin = new Thickness(12, i + 12, 0, 0);

this.RegisterName(
                "myAnimatedBorder", border1);
 
            ThicknessAnimation myThicknessAnimation = new ThicknessAnimation();
            myThicknessAnimation.Duration = TimeSpan.FromSeconds(1.5);
            //myThicknessAnimation.FillBehavior = FillBehavior.HoldEnd;
 
            // Set the From and To properties of the animation.
            // BorderThickness animates from left=1, right=1, top=1, and bottom=1 
            // to left=28, right=28, top=14, and bottom=14 over one and a half seconds.
            myThicknessAnimation.From = new Thickness(1, 1, 1, 1);
            myThicknessAnimation.To = new Thickness(28, 14, 28, 14);
 
            Storyboard.SetTargetName(myThicknessAnimation, "myAnimatedBorder");
            Storyboard.SetTargetProperty(
                myThicknessAnimation, new PropertyPath(XXX.XXXXXXXXXXXX));
 
            // Create a storyboard to apply the animation.
            Storyboard ellipseStoryboard = new Storyboard();
            ellipseStoryboard.Children.Add(myThicknessAnimation);
 
            // Start the storyboard when the Path loads.
            ellipseStoryboard.Begin(this);

ThicknessAnimation myThicknessAnimation = new ThicknessAnimation();
myThicknessAnimation.Duration = TimeSpan.FromSeconds(1.5);
myThicknessAnimation.From = border1.Margin;
myThicknessAnimation.To = new Thickness(28, 14, 28, 14);
border1.BeginAnimation(Border.MarginProperty, myThicknessAnimation);