gistfile1.cs

using System;
using System.Collections.Generic;
using System.Text;
using SHDocVw;
using mshtml;
using System.IO;
using Microsoft.Win32;
using System.Runtime.InteropServices;

namespace bho
{

    [
    ComVisible(true),
    Guid("8a194578-81ea-4850-9911-13ba2d71efbd"),
    ClassInterface(ClassInterfaceType.None)
    ]
    public class BHO:IObjectWithSite
    {
        WebBrowser webBrowser;
        HTMLDocument document
        {
            get
            {
                return (HTMLDocument)webBrowser.Document;
            }
        }
        String domain
        {
            get
            {
                return document.domain;
            }
        }

        public void OnDocumentComplete(object pDisp, ref object URL)
        {
            // here i want to insert a header to the body

        }

        #region BHO Internal Functions
        public static string BHOKEYNAME = "Software\\Microsoft\\Windows\\CurrentVersion\\Explorer\\Browser Helper Objects";

        [ComRegisterFunction]
        public static void RegisterBHO(Type type)
        {
            RegistryKey registryKey = Registry.LocalMachine.OpenSubKey(BHOKEYNAME, true);

            if (registryKey == null)
                registryKey = Registry.LocalMachine.CreateSubKey(BHOKEYNAME);

            string guid = type.GUID.ToString("B");
            RegistryKey ourKey = registryKey.OpenSubKey(guid);

            if (ourKey == null)
                ourKey = registryKey.CreateSubKey(guid);

            ourKey.SetValue("Alright", 1);
            registryKey.Close();
            ourKey.Close();
        }

        [ComUnregisterFunction]
        public static void UnregisterBHO(Type type)
        {
            RegistryKey registryKey = Registry.LocalMachine.OpenSubKey(BHOKEYNAME, true);
            string guid = type.GUID.ToString("B");

            if (registryKey != null)
                registryKey.DeleteSubKey(guid, false);
        }

        public int SetSite(object site)
        {
            if (site != null)
            {
                webBrowser = (WebBrowser)site;
                webBrowser.DocumentComplete += new DWebBrowserEvents2_DocumentCompleteEventHandler(OnDocumentComplete);
            }
            else
            {
                webBrowser.DocumentComplete -= new DWebBrowserEvents2_DocumentCompleteEventHandler(OnDocumentComplete);
                webBrowser = null;
            }
            return 0;
        }

        public int GetSite(ref Guid guid, out IntPtr ppvSite)
        {
            IntPtr punk = Marshal.GetIUnknownForObject(webBrowser);
            int hr = Marshal.QueryInterface(punk, ref guid, out ppvSite);
            Marshal.Release(punk);

            return hr;
        }
        #endregion
    }
}