WPF引用xmlns:i="clr-namespace:System.Windows.Interactivity;assembly=System.Windows.Interactivity"后可以设置很多自定义的行为：

当时当我们有一些自定义的需求时，需要自定义行为，例如给每个控件添加一个双击复制文本的行为。

1. 定义行为

public class MouseDoubleClickCopyTextBehavior : Behavior
     
          {        /// 
      
        /// 需要复制的内容        /// 
        public string CopyText        {            get { return (string)GetValue(CopyTextProperty); }            set { SetValue(CopyTextProperty, value); }        }        public static readonly DependencyProperty CopyTextProperty = DependencyProperty.Register("CopyText", typeof(string), typeof(MouseDoubleClickCopyTextBehavior), new PropertyMetadata(null));        protected override void OnAttached()        {            base.OnAttached();            AssociatedObject.PreviewMouseLeftButtonDown += AssociatedObject_PreviewMouseLeftButtonDown;        }        protected override void OnDetaching()        {            base.OnDetaching();            AssociatedObject.PreviewMouseLeftButtonDown -= AssociatedObject_PreviewMouseLeftButtonDown;        }        void AssociatedObject_PreviewMouseLeftButtonDown(object sender, MouseButtonEventArgs e)        {            if (e.ClickCount >= 2)                Clipboard.SetDataObject(CopyText);        }
     

2. 控件绑定行为