How to get IOleSite interface of the WebBrowser in

How to get IOleSite interface of the WebBrowser in an ActiveX control
//From http://www.cnblogs.com/jonnyyu/archive/2004/02/14/1248.html
//based on Q172763 HOWTO: Retrieve the Top-Level IWebBrowser2 Interface from an ActiveX Control

using System;

using System.ComponentModel;

using System.Windows.Forms;

using System.Drawing;

using System.Reflection;

using System.Security;

using System.Runtime.InteropServices;

using SHDocVw;

 

 

//Use strongname to apply the customized pemission set

[assembly : AssemblyKeyFile(@"c:\key.snk")]

//Q814669 PRB: Strong Named User Controls Do Not render in Internet Explorer

[assembly: System.Security.AllowPartiallyTrustedCallers]

namespace Microsoft.Samples.WinForms.Cs.SimpleControl 

{

 

     public class SimpleControl : System.Windows.Forms.Control 

     {

 

         public SimpleControl() :base() 

         {

              Button btn = new Button();

              btn.Parent = this;

              btn.Text = "Button1";

              btn.Location = new Point(10,10);

              btn.Click += new EventHandler(Btn_OnClick);

              Controls.Add(btn);

         }

        //from shlguid.h

         Guid SID_STopLevelBrowser = new Guid(0x4C96BE40, 0x915C, 0x11CF, 0x99, 0xD3, 0x00, 0xAA, 0x00, 0x4A, 0xE8, 0x37);

         Guid SID_SWebBrowserApp = typeof(SHDocVw.IWebBrowserApp).GUID;

         private void Btn_OnClick(object sender, EventArgs e)

         {

              try

              {

                   Guid guidIServiceProvider = typeof(IServiceProvider).GUID;

                   Guid guidIWebBrowser2 = typeof(SHDocVw.IWebBrowser2).GUID;

                   object objIServiceProvider2;

                   object objIWebBrowser2;

 

              

                   Type typeIOleObject = this.GetType().GetInterface("IOleObject",true);

                //call the method on that interface

                   object oleClientSite = typeIOleObject.InvokeMember("GetClientSite",

                       BindingFlags.Instance|BindingFlags.InvokeMethod|BindingFlags.Public,

                       null,this,null);

                   IServiceProvider serviceProvider = oleClientSite as IServiceProvider;

                   serviceProvider.QueryService(ref SID_STopLevelBrowser,ref guidIServiceProvider, out objIServiceProvider2);

                   serviceProvider = objIServiceProvider2 as IServiceProvider;

                   serviceProvider.QueryService(ref SID_SWebBrowserApp, ref guidIWebBrowser2, out objIWebBrowser2);

                   IWebBrowser2 webBrowser = objIWebBrowser2 as IWebBrowser2;

                   MessageBox.Show(webBrowser.LocationURL);

              }

              catch(Exception ex)

              {

                   System.Diagnostics.Debug.WriteLine(ex.ToString());

              }

 

         }

     }