wpf 用户自定义事件传参

//自定义传参 ，对外联系的参数
public class ImageZoomChangedEventArgs : RoutedEventArgs
    {
        /// <summary>
        /// 放大倍数，1：原始尺寸
        /// </summary>
        public int Zoom { get; set; }
        public ImageZoomChangedEventArgs(RoutedEvent routedEvent, int value) : base(routedEvent)
        {
            this.Zoom = value;
        }
    }

//用户自定义事件
        public delegate void ZoomChangedEventHandler(object sender, EventArgs e);
        public event ZoomChangedEventHandler ZoomChanged
        {
            add
            {
                this.AddHandler(ZoomChangedEvent, value);
            }

            remove
            {
                this.RemoveHandler(ZoomChangedEvent, value);
            }
        }
        public static readonly RoutedEvent ZoomChangedEvent = EventManager.RegisterRoutedEvent("ZoomChanged", RoutingStrategy.Bubble, typeof(ZoomChangedEventHandler), typeof(HZImageViewerEx));

    //触发自定义事件
     void OnPreviewMouseWheel(object sender, MouseWheelEventArgs e)
        {
        this.RaiseEvent(new ImageZoomChangedEventArgs(ZoomChangedEvent, (int)slider.Value));
       }

//外部接收的事件处理方法
private void img_ZoomChanged(object sender, EventArgs e)
{
    var args = (ImageZoomChangedEventArgs)e;
         if(args.Zoom!=)
         {
               ....
          }
 }