C# Internet Explorer DOM using ObjectFromLresult.

[dynamic_sysop]

Howdo, I've been working on this for a couple of days, I did a VB.NET example of this on a forum a few years ago, but C# presented me with a new challenge & it took a while to figure out.

The Idea is to get hold of an open instance of IE ( IE7 in this case ) & grab hold of it's IHTMLDocument2 Interface, giving the ability to manipulate that external Internet Explorer window / grab it's url address, it's html, make it navigate elsewhere, etc...

when this code is added to a project, you must make a reference to Microsoft.mshtml

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Diagnostics;
using System.Drawing;
using System.Runtime.InteropServices;
using System.Text;
using System.Windows.Forms;
using mshtml;
namespace HookBrowser
{
   public partial class Form1 : Form
   {
       public Form1()
       {
           InitializeComponent();
       }
       #region API CALLS
       [DllImport("user32.dll", EntryPoint = "GetClassNameA")]
       public static extern int GetClassName(IntPtr hwnd, StringBuilder lpClassName, int nMaxCount);
       /*delegate to handle EnumChildWindows*/
       public delegate int EnumProc(IntPtr hWnd, ref IntPtr lParam);
       [DllImport("user32.dll")]
       public static extern int EnumChildWindows(IntPtr hWndParent, EnumProc lpEnumFunc, ref  IntPtr lParam);
       [DllImport("user32.dll", EntryPoint = "RegisterWindowMessageA")]
       public static extern int RegisterWindowMessage(string lpString);
       [DllImport("user32.dll", EntryPoint = "SendMessageTimeoutA")]
       public static extern int SendMessageTimeout(IntPtr hwnd, int msg, int wParam, int lParam, int fuFlags, int uTimeout, out int lpdwResult);
       [DllImport("OLEACC.dll")]
       public static extern int ObjectFromLresult(int lResult, ref Guid riid, int wParam, ref IHTMLDocument2 ppvObject);
       public const int SMTO_ABORTIFHUNG = 0x2;
       public Guid IID_IHTMLDocument = new Guid("626FC520-A41E-11CF-A731-00A0C9082637");
       #endregion
       public IHTMLDocument2 document;
       private void button1_Click(object sender, EventArgs e)
       {
           document = documentFromDOM();
           /// check that we have hold of the IHTMLDocument2...
           if (!(bool)(document == null))
           {
               this.Text = document.url;
           }
       }
       private IHTMLDocument2 documentFromDOM()
       {
           Process[] processes = Process.GetProcessesByName("iexplore");
           if (processes.Length > 0)
           {
               IntPtr hWnd = processes[0].MainWindowHandle;
               int lngMsg = 0;
               int lRes;
               EnumProc proc = new EnumProc(EnumWindows);
               EnumChildWindows(hWnd, proc, ref hWnd);
               if (!hWnd.Equals(IntPtr.Zero))
               {
                   lngMsg = RegisterWindowMessage("WM_HTML_GETOBJECT");
                   if (lngMsg != 0)
                   {
                       SendMessageTimeout(hWnd, lngMsg, 0, 0, SMTO_ABORTIFHUNG, 1000, out lRes);
                       if (!(bool)(lRes == 0))
                       {
                           int hr = ObjectFromLresult(lRes, ref IID_IHTMLDocument, 0, ref document);
                           if ((bool)(document == null))
                           {
                               MessageBox.Show("No IHTMLDocument Found!", "Warning");
                           }
                       }
                   }
               }
           }
           return document;
       }
       private int EnumWindows(IntPtr hWnd, ref IntPtr lParam)
       {
           int retVal = 1;
           StringBuilder classname = new StringBuilder(128);
           GetClassName(hWnd, classname, classname.Capacity);
           /// check if the instance we have found is Internet Explorer_Server
           if ((bool)(string.Compare(classname.ToString(), "Internet Explorer_Server") == 0))
           {
               lParam = hWnd;
               retVal = 0;
           }
           return retVal;
       }
   }
}

:)

Edited October 15, 2021 by AWS