【WPF】WPF Behavior 行为 实现鼠标移入按钮自动旋转

1、需要下载 System.Windows.Interactivity.dll  提取码: dc5a 这是微软提供的扩展dll

2、项目引用DLL后，在前端加入代码：

 xmlns:i="clr-namespace:System.Windows.Interactivity;assembly=System.Windows.Interactivity"

3、后台代码：（实现的功能是鼠标移入，旋转360度，鼠标移出，还原）

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Interactivity;
using System.Windows.Media;
using System.Windows.Media.Animation;

namespace WpfStyles
{
    public class RotateBehavior : Behavior<FrameworkElement>
    {
        protected override void OnAttached()
        {
            base.OnAttached();
 　　　　　　// AssociatedObject 是行为的关联对象
　　　　　　 this.AssociatedObject.MouseEnter += AssociatedObject_MouseEnter;
           this.AssociatedObject.MouseLeave += AssociatedObject_MouseLeave;
        }

        private void AssociatedObject_MouseLeave(object sender, System.Windows.Input.MouseEventArgs e)
        {
            var element = sender as FrameworkElement;
            RotateTransform rotateTransform = new RotateTransform();
            element.RenderTransformOrigin = new Point(0.5, 0.5);
            DoubleAnimation animation = new DoubleAnimation(360, 0, new Duration(new TimeSpan(0, 0, 1)), FillBehavior.Stop);
            animation.Completed += (sender1, e1) => rotateTransform.BeginAnimation(RotateTransform.AngleProperty, null);
            rotateTransform.BeginAnimation(RotateTransform.AngleProperty, animation);
            element.RenderTransform = rotateTransform;
        }

        private void AssociatedObject_MouseEnter(object sender, System.Windows.Input.MouseEventArgs e)
        {
            var element = sender as FrameworkElement;
            RotateTransform rotateTransform = new RotateTransform();
            element.RenderTransformOrigin = new Point(0.5, 0.5);
            DoubleAnimation animation = new DoubleAnimation(0, 360, new Duration(new TimeSpan(0, 0, 0, 1)), FillBehavior.Stop);
            animation.Completed += (sender1, e1) => rotateTransform.BeginAnimation(RotateTransform.AngleProperty, null);
            //animation.RepeatBehavior = RepeatBehavior.Forever;
            //animation.AutoReverse = true;
            rotateTransform.BeginAnimation(RotateTransform.AngleProperty, animation);
            element.RenderTransform = rotateTransform;
        }

        protected override void OnDetaching()
        {
            base.OnDetaching();
        }
    }
}

4、使用，除了前面提到的引用

 xmlns:i="clr-namespace:System.Windows.Interactivity;assembly=System.Windows.Interactivity"

只需要再加一行代码即可：

 <Button  Content="旋转" Grid.Row="1" Grid.Column="5">
            <i:Interaction.Behaviors>
                <local:RotateBehavior></local:RotateBehavior>
            </i:Interaction.Behaviors>
</Button>