[WPF]CefSharp的触屏功能 - 滚动功能

CefSharp是谷歌浏览器的内核开源库，WPF的相关库为CefSharp.wpf，我用的是49.0.1版本的CefSharp.Wpf，但貌似在并不支持触屏的滚动功能，所以就自己写了个附加的触屏功能，暂时只有滚动功能，代码如下：

1.附加类及属性：

    /// 

    /// 附加功能:CEF的触屏功能
    /// 
    public class CefTouch : DependencyObject
    {

        #region Property.Attached - Scrolling

        public static bool GetScrolling(DependencyObject obj)
        {
            return (bool)obj.GetValue(ScrollingProperty);
        }

        public static void SetScrolling(DependencyObject obj, bool value)
        {
            obj.SetValue(ScrollingProperty, value);
        }

        /// 
 G/S:滚动功能 
        public bool Scrolling
        {
            get { return (bool)GetValue(ScrollingProperty); }
            set { SetValue(ScrollingProperty, value); }
        }

        public static readonly DependencyProperty ScrollingProperty =
            DependencyProperty.RegisterAttached("Scrolling", typeof(bool), typeof(CefTouch), new UIPropertyMetadata(false, _OnScrollingChanged));

        static void _OnScrollingChanged(DependencyObject sender, DependencyPropertyChangedEventArgs e)
        {
            if (!(sender is FrameworkElement _target)) { return; }

            if ((bool)e.NewValue)
            {
                _target.Loaded += _OnLoaded;
            }
            else
            {
                _OnUnloaded(_target, new RoutedEventArgs());
            }
        }

        #endregion

        #region Functions.Scrolling

        /// 
 G/S:捕获的触屏数据 
        private static readonly Dictionary _Captures = new Dictionary();

        private static void _OnLoaded(object sender, RoutedEventArgs e)
        {
            System.Diagnostics.Debug.WriteLine("Scrolling Touched Loaded");

            if (!(sender is FrameworkElement _target)) { return; }

            _target.Unloaded += _OnUnloaded;

            _target.TouchDown += _OnDown;
            _target.TouchMove += _OnMove;
            _target.TouchUp += _OnUp;
            _target.TouchLeave += _OnUp;
        }

        private static void _OnUnloaded(object sender, RoutedEventArgs e)
        {
            System.Diagnostics.Debug.WriteLine("Scrolling Touched Unloaded");

            if (!(sender is FrameworkElement _target)) { return; }

            _Captures.Remove(sender);

            _target.Loaded -= _OnLoaded;
            _target.Unloaded -= _OnUnloaded;

            _target.TouchDown -= _OnDown;
            _target.TouchMove -= _OnMove;
            _target.TouchUp -= _OnUp;
            _target.TouchLeave -= _OnUp;
        }

        private static void _OnDown(object sender, TouchEventArgs e)
        {
            System.Diagnostics.Debug.WriteLine("Scrolling Touch Down");
            IWebBrowser _webBrowser = null;
            CefTouchCapture _capture = null;
            if (!_Captures.ContainsKey(sender))
            {
                _webBrowser = (sender as IWebBrowser);
                if (_webBrowser == null)
                {
                    _webBrowser = WPFUntity.FindFirstVisualChild(sender as DependencyObject);
                }
            }
            else
            {
                _capture = _Captures[sender];
                if (_capture == null) { return; }
                _webBrowser = _capture.Browser;
            }

            if (_webBrowser == null) { return; }
            if (_capture == null)
            {
                _capture = new CefTouchCapture();
            }
            _capture.IsMouseDown = true;
            _capture.Point = null;
            _capture.MoveTime = DateTime.Now;
            _capture.Browser = _webBrowser;
            _capture.Host = _webBrowser.GetBrowser().GetHost();
            _Captures[sender] = _capture;
        }

        private static void _OnUp(object sender, TouchEventArgs e)
        {
            System.Diagnostics.Debug.WriteLine("Scrolling Touch Up");
            if (!_Captures.ContainsKey(sender)) { return; }

            var _capture = _Captures[sender];
            if (_capture == null) { return; }

            _capture.IsMouseDown = false;
            _capture.Point = null;
        }

        private static void _OnMove(object sender, TouchEventArgs e)
        {
            System.Diagnostics.Debug.WriteLine("Scrolling Touch Move");
            if (!_Captures.ContainsKey(sender)) { return; }

            var _capture = _Captures[sender];
            if (_capture == null) { return; }

            if ((DateTime.Now - _capture.MoveTime).TotalMilliseconds < 150) { return; }

            if (!(sender is IInputElement _ielement)) { return; }

            if (_capture.Host != null && _capture.IsMouseDown)
            {
                System.Diagnostics.Debug.WriteLine("Scrolling Touch Move - Moved");
                _capture.MoveTime = DateTime.Now;

                TouchPoint _tPoint = e.GetTouchPoint(_ielement);
                Point _newPoint = _tPoint.Position;

                if (!_capture.Point.HasValue)
                {
                    _capture.Point = _newPoint;
                }

                int _x = (int)_newPoint.X;
                int _y = (int)_newPoint.Y;
                int _oldX = (int)_capture.Point.Value.X;
                int _oldy = (int)_capture.Point.Value.Y;

                _capture.Host.SendMouseWheelEvent(_x, _y, 0, _y - _oldy, CefEventFlags.MiddleMouseButton);
                _capture.Point = _newPoint;
            }
        }

        #endregion

        #region Class

        /// 

        /// Class:CEF的触屏捕获
        /// 
        internal class CefTouchCapture
        {

            public DateTime MoveTime { get; set; }

            public IBrowserHost Host { get; set; }
            public IWebBrowser Browser { get; set; }
            public bool IsMouseDown { get; set; }
            public Point? Point { get; set; }

        }

        #endregion


    }

2.在Xaml上的使用方式：