C#彻底解决Web Browser 跨域读取Iframes内容

用C# winform的控件web browser 读取网页内容，分析一下数据，做一些采集工作。

如果是同一个域名下面还是好办的，基本上用HtmlAgilityPack就完全可以解决问题。 

但是现在遇到跨域问题，比如我需要打开页面上存在的广告联盟的地址，进行保存。 

这就是牵扯到跨域。 一般的错误是：拒绝访问。

"Access is denied. (Exception from HRESULT: 0x80070005 (E_ACCESSDENIED))"。 

因为你没有在这个网站去修改另一个网站数据的权利。 

怎么办？很困恼吧。现在就告诉大家一个好办法。 

直接上代码了。 

工具类，大家保存成一个类。需要引用mshtml

using System;
using System.Runtime.InteropServices;
using System.Windows.Forms;
using mshtml;

namespace WebBrowserTest
{

    // This is the COM IServiceProvider interface, not System.IServiceProvider .Net interface! 

    [ComImport(), ComVisible(true), Guid("6D5140C1-7436-11CE-8034-00AA006009FA"),

    InterfaceTypeAttribute(ComInterfaceType.InterfaceIsIUnknown)]

    public interface IServiceProvider
    {

        [return: MarshalAs(UnmanagedType.I4)]

        [PreserveSig]

        int QueryService(ref Guid guidService, ref Guid riid, [MarshalAs(UnmanagedType.Interface)] out object ppvObject);

    }

    public enum OLECMDF
    {

        OLECMDF_DEFHIDEONCTXTMENU = 0x20,

        OLECMDF_ENABLED = 2,

        OLECMDF_INVISIBLE = 0x10,

        OLECMDF_LATCHED = 4,

        OLECMDF_NINCHED = 8,

        OLECMDF_SUPPORTED = 1

    }

    public enum OLECMDID
    {

        OLECMDID_PAGESETUP = 8,

        OLECMDID_PRINT = 6,

        OLECMDID_PRINTPREVIEW = 7,

        OLECMDID_PROPERTIES = 10,

        OLECMDID_SAVEAS = 4

    }

    public enum OLECMDEXECOPT
    {

        OLECMDEXECOPT_DODEFAULT,

        OLECMDEXECOPT_PROMPTUSER,

        OLECMDEXECOPT_DONTPROMPTUSER,

        OLECMDEXECOPT_SHOWHELP

    }

    [ComImport, Guid("D30C1661-CDAF-11d0-8A3E-00C04FC9E26E"), TypeLibType(TypeLibTypeFlags.FOleAutomation | TypeLibTypeFlags.FDual | TypeLibTypeFlags.FHidden)]

    public interface IWebBrowser2
    {

        [DispId(100)]

        void GoBack();

        [DispId(0x65)]

        void GoForward();

        [DispId(0x66)]

        void GoHome();

        [DispId(0x67)]

        void GoSearch();

        [DispId(0x68)]

        void Navigate([In] string Url, [In] ref object flags, [In] ref object targetFrameName, [In] ref object postData, [In] ref object headers);

        [DispId(-550)]

        void Refresh();

        [DispId(0x69)]

        void Refresh2([In] ref object level);

        [DispId(0x6a)]

        void Stop();

        [DispId(200)]

        object Application { [return: MarshalAs(UnmanagedType.IDispatch)] get; }

        [DispId(0xc9)]

        object Parent { [return: MarshalAs(UnmanagedType.IDispatch)] get; }

        [DispId(0xca)]

        object Container { [return: MarshalAs(UnmanagedType.IDispatch)] get; }

        [DispId(0xcb)]

        object Document { [return: MarshalAs(UnmanagedType.IDispatch)] get; }

        [DispId(0xcc)]

        bool TopLevelContainer { get; }

        [DispId(0xcd)]

        string Type { get; }

        [DispId(0xce)]

        int Left { get; set; }

        [DispId(0xcf)]

        int Top { get; set; }

        [DispId(0xd0)]

        int Width { get; set; }

        [DispId(0xd1)]

        int Height { get; set; }

        [DispId(210)]

        string LocationName { get; }

        [DispId(0xd3)]

        string LocationURL { get; }

        [DispId(0xd4)]

        bool Busy { get; }

        [DispId(300)]

        void Quit();

        [DispId(0x12d)]

        void ClientToWindow(out int pcx, out int pcy);

        [DispId(0x12e)]

        void PutProperty([In] string property, [In] object vtValue);

        [DispId(0x12f)]

        object GetProperty([In] string property);

        [DispId(0)]

        string Name { get; }

        [DispId(-515)]

        int HWND { get; }

        [DispId(400)]

        string FullName { get; }

        [DispId(0x191)]

        string Path { get; }

        [DispId(0x192)]

        bool Visible { get; set; }

        [DispId(0x193)]

        bool StatusBar { get; set; }

        [DispId(0x194)]

        string StatusText { get; set; }

        [DispId(0x195)]

        int ToolBar { get; set; }

        [DispId(0x196)]

        bool MenuBar { get; set; }

        [DispId(0x197)]

        bool FullScreen { get; set; }

        [DispId(500)]

        void Navigate2([In] ref object URL, [In] ref object flags, [In] ref object targetFrameName, [In] ref object postData, [In] ref object headers);

        [DispId(0x1f5)]

        OLECMDF QueryStatusWB([In] OLECMDID cmdID);

        [DispId(0x1f6)]

        void ExecWB([In] OLECMDID cmdID, [In] OLECMDEXECOPT cmdexecopt, ref object pvaIn, IntPtr pvaOut);

        [DispId(0x1f7)]

        void ShowBrowserBar([In] ref object pvaClsid, [In] ref object pvarShow, [In] ref object pvarSize);

        [DispId(-525)]

        WebBrowserReadyState ReadyState { get; }

        [DispId(550)]

        bool Offline { get; set; }

        [DispId(0x227)]

        bool Silent { get; set; }

        [DispId(0x228)]

        bool RegisterAsBrowser { get; set; }

        [DispId(0x229)]

        bool RegisterAsDropTarget { get; set; }

        [DispId(0x22a)]

        bool TheaterMode { get; set; }

        [DispId(0x22b)]

        bool AddressBar { get; set; }

        [DispId(0x22c)]

        bool Resizable { get; set; }

    }

    class CorssDomainHelper
    {

        private static Guid IID_IWebBrowserApp = new Guid("0002DF05-0000-0000-C000-000000000046");

        private static Guid IID_IWebBrowser2 = new Guid("D30C1661-CDAF-11D0-8A3E-00C04FC9E26E");

        // Utility for IE cross domain access 

        // Returns null in case of failure. 

        public static IHTMLDocument3 GetDocumentFromWindow(IHTMLWindow2 htmlWindow)
        {

            if (htmlWindow == null)
            {
                return null;
            }

            // First try the usual way to get the document. 

            try
            {

                IHTMLDocument2 doc = htmlWindow.document;

                return (IHTMLDocument3)doc;

            }

            catch (COMException comEx)
            {

                // I think COMException won't be ever fired but just to be sure ... 

            }

            catch (UnauthorizedAccessException)
            {

            }

            catch (Exception ex)
            {
                return null;
            }

            // At this point the error was E_ACCESSDENIED because the frame contains a document from another domain. 
            // IE tries to prevent a cross frame scripting security issue. 

            try
            {

                // Convert IHTMLWindow2 to IWebBrowser2 using IServiceProvider. 
                IServiceProvider sp = (IServiceProvider)htmlWindow;
                // Use IServiceProvider.QueryService to get IWebBrowser2 object. 
                Object brws = null;
                sp.QueryService(ref IID_IWebBrowserApp, ref IID_IWebBrowser2, out brws);
                // Get the document from IWebBrowser2. 
                IWebBrowser2 browser = (IWebBrowser2)(brws);
                return (IHTMLDocument3)browser.Document;
            }

            catch (Exception ex)
            {
                Console.WriteLine(ex);
            }
            return null;
        }
    }
}

调用方法：

public void test()
        {
            WebBrowser browser = new WebBrowser();

            HTMLDocument doc = (HTMLDocument)browser.Document.DomDocument;

            for (int i = 0; i < browser.Document.Window.Frames.Count; i++)
            {

                IHTMLDocument3 baiduDoc = CorssDomainHelper.GetDocumentFromWindow(browser.Document.Window.Frames[i].DomWindow

                    as IHTMLWindow2);

                if (baiduDoc != null && baiduDoc.documentElement != null && baiduDoc.documentElement.document != null)
                {

                    IHTMLElementCollection linkss = ((HTMLDocument)(baiduDoc.documentElement.document)).links;

                    foreach (mshtml.IHTMLElement element in linkss)
                    {

                        //加入你的代码就可以了。

                    }
                }
            }
        }

原文出自：http://www.cnblogs.com/Leo_wl/p/3181353.html