WebBrowserControl:访问Frame的属性时出现UnauthorizedAccessException

Question

我使用默认的WebBrowser控件在C#中编写了一个非常小的网站bot.实际上几乎所有东西都按照预期的方式工作,但我似乎在自动化的最后一步有问题.

该网站是使用几个iframe构建的.这不是什么大不了的事,因为我只是使用这些框架及其元素

webBrowser1.Document.Window.Frames[0].Document.GetElementById("element").InvokeMember("click");

但是,当IFRAME的源托管在与实际网站不同的域上时,这不起作用.当我在互联网上搜索我的问题的答案时,我偶然发现了一篇提到这个特定问题的MSDN文章,他们指的是跨站点脚本的安全措施,这可能是导致此错误的原因.

我无法找到一种禁用此功能的方法,所以我继续前进并决定重新编码所有内容以使用geckofx-12而不是默认(基于IE)的Web浏览器控件,但我遇到了类似的问题......

我的问题是:有什么方法可以绕过这种烦人的行为吗？我真的不关心安全问题或者是否使用geckofx或默认的Web浏览器控件,我只想以编程方式访问托管在不同域上的站点的元素,而不会遇到UnauthorizedAccessException.

我很想得到那些大师们的建议.

Answer 1

您无法访问来自不同域的帧.这是一个安全功能.它有一点点破解:

 public class CrossFrameIE
{
    // Returns null in case of failure.
    public static IHTMLDocument2 GetDocumentFromWindow(IHTMLWindow2 htmlWindow)
    {
        if (htmlWindow == null)
        {
            return null;
        }

        // First try the usual way to get the document.
        try
        {
            IHTMLDocument2 doc = htmlWindow.document;                

            return doc;
        }
        catch (COMException comEx)
        {
            // I think COMException won't be ever fired but just to be sure ...
            if (comEx.ErrorCode != E_ACCESSDENIED)
            {
                return null;
            }
        }
        catch (System.UnauthorizedAccessException)
        {
        }
        catch
        {
            // Any other error.
            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 (IHTMLDocument2)browser.Document;
        }
        catch
        {
        }

        return null;
    }

    private const int E_ACCESSDENIED = unchecked((int)0x80070005L);
    private static Guid IID_IWebBrowserApp = new Guid("0002DF05-0000-0000-C000-000000000046");
    private static Guid IID_IWebBrowser2 = new Guid("D30C1661-CDAF-11D0-8A3E-00C04FC9E26E");
}

// 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);
}

Answer 2

我更新了 Daniel Bogdan 稍微发布的 hack 以使用扩展方法，并为您提供一种无需进入 mshtml 命名空间即可调用它的方法：

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

namespace TradeAutomation
{
    public static class CrossFrameIE
    {
        private static FieldInfo ShimManager = typeof(HtmlWindow).GetField("shimManager", BindingFlags.NonPublic | BindingFlags.Instance);
        private static ConstructorInfo HtmlDocumentCtor = typeof(HtmlDocument).GetConstructors(BindingFlags.NonPublic | BindingFlags.Instance)[0];

        public static HtmlDocument GetDocument(this HtmlWindow window)
        {
            var rawDocument = (window.DomWindow as IHTMLWindow2).GetDocumentFromWindow();

            var shimManager = ShimManager.GetValue(window);

            var htmlDocument = HtmlDocumentCtor
                .Invoke(new[] { shimManager, rawDocument }) as HtmlDocument;

            return htmlDocument;
        }


        // Returns null in case of failure.
        public static IHTMLDocument2 GetDocumentFromWindow(this IHTMLWindow2 htmlWindow)
        {
            if (htmlWindow == null)
            {
                return null;
            }

            // First try the usual way to get the document.
            try
            {
                IHTMLDocument2 doc = htmlWindow.document;

                return doc;
            }
            catch (COMException comEx)
            {
                // I think COMException won't be ever fired but just to be sure ...
                if (comEx.ErrorCode != E_ACCESSDENIED)
                {
                    return null;
                }
            }
            catch (System.UnauthorizedAccessException)
            {
            }
            catch
            {
                // Any other error.
                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 (IHTMLDocument2)browser.Document;
            }
            catch
            {
            }

            return null;
        }

        private const int E_ACCESSDENIED = unchecked((int)0x80070005L);
        private static Guid IID_IWebBrowserApp = new Guid("0002DF05-0000-0000-C000-000000000046");
        private static Guid IID_IWebBrowser2 = new Guid("D30C1661-CDAF-11D0-8A3E-00C04FC9E26E");
    }

    // 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);
    }
}

用法：

webBrowser1.Document.Window.Frames["main"].GetDocument();

正如我在上面的评论中提到的，您还需要添加对 SHDocVw 的引用。您可以在此处找到相关说明：Add reference 'SHDocVw' in C# project using Visual C# 2010 Express

Answer 3

我还没有尝试过这个，但更改文档域显然是有效的。

使用 geckofx 12 看起来这可能是由 nsIDOMHTMLDocument.SetDomainAttribute 完成的（GeckoDocument.Domain 没有设置器，但您可以轻松添加它）

IE。如果您更改文档的域以匹配子框架，您也许能够访问它。