问题
I am developing a BHO for IE in C# that controls the navigation flow of IE by checking the URL in onBeforeNavigateEvent.
Everything works fine except that when a link is opened in a new tab then some of the tabs opened as About:Blank.
I have checked the logs and also debugged the BHO no exception is thrown. However in the case of About:Blank BHO is initiated SetSite and GetSite methods are called but navigation event is not fired.
Also it happens when links are opened in new tab rapidly.
For testing purpose I disabled the addon and IE worked fine i.e. no About:Blank page.
Loading time of BHO is 0.1s and Navigation time is 0.5s
So, what could be the issue ?
The source I followed to build this BHO is here
Current Environment: IE 11, Windows 10
Interop.cs
using System;
using System.Runtime.InteropServices;
namespace IE_BHO
{
[
ComImport(),
ComVisible(true),
InterfaceType(ComInterfaceType.InterfaceIsIUnknown),
Guid("FC4801A3-2BA9-11CF-A229-00AA003D7352")
]
interface IObjectWithSite
{
[PreserveSig]
int SetSite([In, MarshalAs(UnmanagedType.IUnknown)] object site);
[PreserveSig]
int GetSite(ref Guid guid, out IntPtr ppvSite);
}
[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)]
public struct OLECMDTEXT
{
public uint cmdtextf;
public uint cwActual;
public uint cwBuf;
[MarshalAs(UnmanagedType.ByValTStr, SizeConst = 100)]
public char rgwz;
}
[StructLayout(LayoutKind.Sequential)]
public struct OLECMD
{
public uint cmdID;
public uint cmdf;
}
[ComImport(), ComVisible(true),
Guid("B722BCCB-4E68-101B-A2BC-00AA00404770"),
InterfaceTypeAttribute(ComInterfaceType.InterfaceIsIUnknown)]
public interface IOleCommandTarget
{
[return: MarshalAs(UnmanagedType.I4)]
[PreserveSig]
int QueryStatus(
[In] IntPtr pguidCmdGroup,
[In, MarshalAs(UnmanagedType.U4)] uint cCmds,
[In, Out, MarshalAs(UnmanagedType.Struct)] ref OLECMD prgCmds,
//This parameter must be IntPtr, as it can be null
[In, Out] IntPtr pCmdText);
[return: MarshalAs(UnmanagedType.I4)]
[PreserveSig]
int Exec(
//[In] ref Guid pguidCmdGroup,
//have to be IntPtr, since null values are unacceptable
//and null is used as default group!
[In] IntPtr pguidCmdGroup,
[In, MarshalAs(UnmanagedType.U4)] uint nCmdID,
[In, MarshalAs(UnmanagedType.U4)] uint nCmdexecopt,
[In] IntPtr pvaIn,
[In, Out] IntPtr pvaOut);
}
[Guid("6D5140C1-7436-11CE-8034-00AA006009FA")]
[InterfaceType(1)]
public interface IServiceProvider
{
int QueryService(ref Guid guidService, ref Guid riid, out IntPtr ppvObject);
}
[
ComVisible(true),
Guid("4C1D2E51-018B-4A7C-8A07-618452573E42"),
InterfaceType(ComInterfaceType.InterfaceIsDual)
]
public interface IExtension
{
[DispId(1)]
string ActivateEndPoint(string licenseKey, string userAgent);
}
}
BHO.cs
using Microsoft.Win32;
using SHDocVw;
using System;
using System.Runtime.InteropServices;
using System.Runtime.InteropServices.Expando;
using System.Security.Permissions;
using System.Threading.Tasks;
using mshtml;
using System.Reflection;
using System.Diagnostics;
namespace IE_BHO
{
[
SecurityPermission(SecurityAction.LinkDemand, Flags = SecurityPermissionFlag.UnmanagedCode),
ComVisible(true),
Guid("BDCB9FDA-8370-40D9-96C9-9D4B4C25C0D8"),
ClassInterface(ClassInterfaceType.None),
ProgId("myExtension"),
ComDefaultInterface(typeof(IExtension))
]
public class BHO : IObjectWithSite, IOleCommandTarget, IExtension
{
object _site;
IWebBrowser2 _webBrowser2;
#region Implementation of IObjectWithSite
int IObjectWithSite.SetSite(object site)
{
_site = site;
if (site != null)
{
var serviceProv = (IServiceProvider)_site;
var guidIWebBrowserApp = Marshal.GenerateGuidForType(typeof(IWebBrowserApp));
var guidIWebBrowser2 = Marshal.GenerateGuidForType(typeof(IWebBrowser2));
IntPtr intPtr;
serviceProv.QueryService(ref guidIWebBrowserApp, ref guidIWebBrowser2, out intPtr);
_webBrowser2 = (IWebBrowser2)Marshal.GetObjectForIUnknown(intPtr);
((DWebBrowserEvents2_Event)_webBrowser2).BeforeNavigate2 += OnBeforeNavigate2;
((DWebBrowserEvents2_Event)_webBrowser2).BeforeScriptExecute += S2_BeforeScriptExecute;
((DWebBrowserEvents2_Event)_webBrowser2).DownloadComplete += BHO_DownloadComplete;
}
else
{
((DWebBrowserEvents2_Event)_webBrowser2).BeforeNavigate2 -= OnBeforeNavigate2;
((DWebBrowserEvents2_Event)_webBrowser2).BeforeScriptExecute -= S2_BeforeScriptExecute;
((DWebBrowserEvents2_Event)_webBrowser2).DownloadComplete -= BHO_DownloadComplete;
_webBrowser2 = null;
}
return 0;
}
int IObjectWithSite.GetSite(ref Guid guid, out IntPtr ppvSite)
{
IntPtr punk = Marshal.GetIUnknownForObject(_webBrowser2);
int hr = Marshal.QueryInterface(punk, ref guid, out ppvSite);
Marshal.Release(punk);
return hr;
}
public void OnBeforeNavigate2(object pDisp, ref object URL, ref object Flags, ref object TargetFrameName, ref object PostData, ref object Headers, ref bool Cancel)
{
try
{
UrlObj dto = UrlManager.CheckUrl(URL.ToString());
if (dto.IsInList)
{
Cancel = true;
_webBrowser2.Navigate2("www.google.com");
}
}
catch (Exception ex)
{
}
}
private void S2_BeforeScriptExecute(object pDispWindow)
{
ExposeMethodstoJS();
}
private void BHO_DownloadComplete()
{
ExposeMethodstoJS();
}
private void ExposeMethodstoJS(string calledBy)
{
try
{
HTMLDocument doc = _webBrowser.Document as HTMLDocument;
if (doc != null)
{
IHTMLWindow2 tmpWindow = doc.parentWindow;
dynamic window = tmpWindow;
IExpando windowEx = (IExpando)window;
PropertyInfo p = windowEx.AddProperty("myExtension");
p.SetValue(windowEx, this);
}
}
catch (Exception ex)
{
}
}
#endregion
#region Implementation of IOleCommandTarget
int IOleCommandTarget.QueryStatus(IntPtr pguidCmdGroup, uint cCmds, ref OLECMD prgCmds, IntPtr pCmdText)
{
return 0;
}
int IOleCommandTarget.Exec(IntPtr pguidCmdGroup, uint nCmdID, uint nCmdexecopt, IntPtr pvaIn, IntPtr pvaOut)
{
return 0;
}
#endregion
#region Implementation of IExtension
string IExtension.GetDetails()
{
return "Methods Exposed";
}
#endregion
#region COMRegistration
[ComRegisterFunction]
public static void RegisterBHO(Type type)
{
RegistryKey registryKey = Registry.LocalMachine.CreateSubKey(@"Software\Microsoft\Windows\CurrentVersion\Explorer\Browser Helper Objects");
RegistryKey guidKey = registryKey.CreateSubKey(type.GUID.ToString("B"));
registryKey.Close();
guidKey.Close();
}
[ComUnregisterFunction]
public static void UnregisterBHO(Type type)
{
RegistryKey registryKey = Registry.LocalMachine.OpenSubKey(@"Software\Microsoft\Windows\CurrentVersion\Explorer\Browser Helper Objects", true);
string guid = type.GUID.ToString("B");
if (registryKey != null)
{
registryKey.DeleteSubKey(guid, false);
}
}
#endregion COMRegistration
}
}
回答1:
Which version of IE and OS are you using?
I think the issue occurs because the new tab is opened and navigated at almost the same time. For the detailed information, you could refer to this link.
You could also try the resolution in the article: Install the most recent cumulative security update for Internet Explorer.
来源：https://stackoverflow.com/questions/62709619/ie-opening-new-tab-aboutblank-instead-of-webpage