ExtendedWebBrowser.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace hikssldemo
{

        public class ExtendedWebBrowser : System.Windows.Forms.WebBrowser
        {
            System.Windows.Forms.AxHost.ConnectionPointCookie cookie;
            WebBrowserExtendedEvents events;

            //This method will be called to give you a chance to create your own event sink
            protected override void CreateSink()
            {
                //MAKE SURE TO CALL THE BASE or the normal events won't fire
                base.CreateSink();
                events = new WebBrowserExtendedEvents(this);
                cookie = new System.Windows.Forms.AxHost.ConnectionPointCookie(this.ActiveXInstance, events, typeof(DWebBrowserEvents2));
            }

            protected override void DetachSink()
            {
                if (null != cookie)
                {
                    cookie.Disconnect();
                    cookie = null;
                }
                base.DetachSink();
            }

            //This new event will fire when the page is navigating
            public event EventHandler<WebBrowserExtendedNavigatingEventArgs> BeforeNavigate;
            public event EventHandler<WebBrowserExtendedNavigatingEventArgs> BeforeNewWindow;

            protected void OnBeforeNewWindow(string url, out bool cancel)
            {
                EventHandler<WebBrowserExtendedNavigatingEventArgs> h = BeforeNewWindow;
                WebBrowserExtendedNavigatingEventArgs args = new WebBrowserExtendedNavigatingEventArgs(url, null);
                if (null != h)
                {
                    h(this, args);
                }
                cancel = args.Cancel;
            }

            protected void OnBeforeNavigate(string url, string frame, out bool cancel)
            {
                EventHandler<WebBrowserExtendedNavigatingEventArgs> h = BeforeNavigate;
                WebBrowserExtendedNavigatingEventArgs args = new WebBrowserExtendedNavigatingEventArgs(url, frame);
                if (null != h)
                {
                    h(this, args);
                }
                //Pass the cancellation chosen back out to the events
                cancel = args.Cancel;
            }
            //This class will capture events from the WebBrowser
            class WebBrowserExtendedEvents : System.Runtime.InteropServices.StandardOleMarshalObject, DWebBrowserEvents2
            {
                ExtendedWebBrowser _Browser;
                public WebBrowserExtendedEvents(ExtendedWebBrowser browser) { _Browser = browser; }

                //Implement whichever events you wish
                public void BeforeNavigate2(object pDisp, ref object URL, ref object flags, ref object targetFrameName, ref object postData, ref object headers, ref bool cancel)
                {
                    _Browser.OnBeforeNavigate((string)URL, (string)targetFrameName, out cancel);
                }

                public void NewWindow3(object pDisp, ref bool cancel, ref object flags, ref object URLContext, ref object URL)
                {
                    _Browser.OnBeforeNewWindow((string)URL, out cancel);
                }

            }
            [System.Runtime.InteropServices.ComImport(), System.Runtime.InteropServices.Guid("34A715A0-6587-11D0-924A-0020AFC7AC4D"),
            System.Runtime.InteropServices.InterfaceTypeAttribute(System.Runtime.InteropServices.ComInterfaceType.InterfaceIsIDispatch),
            System.Runtime.InteropServices.TypeLibType(System.Runtime.InteropServices.TypeLibTypeFlags.FHidden)]
            public interface DWebBrowserEvents2
            {

                [System.Runtime.InteropServices.DispId(250)]
                void BeforeNavigate2(
                    [System.Runtime.InteropServices.In,
                System.Runtime.InteropServices.MarshalAs(System.Runtime.InteropServices.UnmanagedType.IDispatch)] object pDisp,
                    [System.Runtime.InteropServices.In] ref object URL,
                    [System.Runtime.InteropServices.In] ref object flags,
                    [System.Runtime.InteropServices.In] ref object targetFrameName, [System.Runtime.InteropServices.In] ref object postData,
                    [System.Runtime.InteropServices.In] ref object headers,
                    [System.Runtime.InteropServices.In,
                System.Runtime.InteropServices.Out] ref bool cancel);
                [System.Runtime.InteropServices.DispId(273)]
                void NewWindow3(
                    [System.Runtime.InteropServices.In,
                System.Runtime.InteropServices.MarshalAs(System.Runtime.InteropServices.UnmanagedType.IDispatch)] object pDisp,
                    [System.Runtime.InteropServices.In, System.Runtime.InteropServices.Out] ref bool cancel,
                    [System.Runtime.InteropServices.In] ref object flags,
                    [System.Runtime.InteropServices.In] ref object URLContext,
                    [System.Runtime.InteropServices.In] ref object URL);

            }
        }

        public class WebBrowserExtendedNavigatingEventArgs : System.ComponentModel.CancelEventArgs
        {
            private string _Url;
            public string Url
            {
                get { return _Url; }
            }

            private string _Frame;
            public string Frame
            {
                get { return _Frame; }
            }

            public WebBrowserExtendedNavigatingEventArgs(string url, string frame)
                : base()
            {
                _Url = url;
                _Frame = frame;
            }
        }

    }