PointAnimation定位自定义UserControl属性

Question

I am attempting to animate the position of a UserControl I have created. My problem is very similar to this question asked on MSDN, without an answer sadly.

https://social.msdn.microsoft.com/Forums/vstudio/en-US/11ce8aaa-1059-4fe5-8f4d-0fa7978e6ff2/using-pointanimation-to-move-a-control?forum=wpf

To summarize, I have a created a Point type dependency property named 'Position' which I use to specify the UserControl's place on the UI, and would like to animate the UserConrol to a new location.

My problem is a syntax one i believe, i am unsure of the right syntax to target my UserControl property (in code-behind).

public class SubContainer : Control 
{ 
 public static readonly DependencyProperty PositionProperty; 

 static SubContainer() 
 { 
    DefaultStyleKeyProperty.OverrideMetadata(typeof(SubContainer), 
        new FrameworkPropertyMetadata(typeof(SubContainer))); 

    PositionProperty = DependencyProperty.Register( 
        "Position", 
        typeof(Point), 
        typeof(SubContainer), 
        new PropertyMetadata(new Point(0, 0))); 
 } 

 public Point Position 
 { 
    get { return (Point)GetValue(PositionProperty); } 
    set { SetValue(PositionProperty, value); } 
 } 

And then my Animation:

        public void BoxTransition()
    {
        Point destination = new Point(70, 300);
        SubContainer box = (MainContent.Children[0] as Container).Children[0] as SubContainer;
        PointAnimation transition = new PointAnimation();
        TimeSpan timespan = TimeSpan.FromSeconds(2);

        this.RegisterName("Target", box.Position);
        Transition.From = box.Position;
        Transition.To = destination;
        Storyboard.SetTargetName(transition, "Target");
        Storyboard.SetTargetProperty(transition, new PropertyPath(box.Position));
        Storyboard bTransition = new Storyboard();
        bTransition.Children.Add(transition);
        bTransition.Begin();

    }

I get the following error:

Object 'System.Windows.Point' cannot be used as an accessor parameter for a PropertyPath. An accessor parameter must be DependencyProperty, PropertyInfo, or PropertyDescriptor.

Any alternatives to animate my control would also be greatly appreciated!

Answer 1

OK so problem solved. Use Expression Blend for all your animation needs. The end ;)

Answer 2

WPF allows to directly start an animation of a UIElement property without a Storyboard.

You wouldn't need more code than this:

var transition = new PointAnimation
{
    To = new Point(70, 300),
    Duration = TimeSpan.FromSeconds(2)
};

box.BeginAnimation(SubContainer.PositionProperty, transition);

Note that the above does not set the From property of the PointAnimation. That way the animation will start from the current value of the Position property.

---

As an alternative to the Position property you may put your SubContainer control in a Canvas

<Canvas>
    <local:SubContainer x:Name="box" Canvas.Left="0" Canvas.Top="0" .../>
</Canvas>

and animate its Canvas.Left and Canvas.Top properties:

var duration = TimeSpan.FromSeconds(2);
box.BeginAnimation(Canvas.LeftProperty,
    new DoubleAnimation { To = 70, Duration = duration });
box.BeginAnimation(Canvas.TopProperty,
    new DoubleAnimation { To = 300, Duration = duration });