Blocking dialogs in .NET WebBrowser control

Question

I have a .NET 2.0 WebBrowser control used to navigate some pages with no user interaction (don\'t ask...long story). Because of the user-less nature of thi

Answer 1

window.showModelessDialog and window.showModalDialog can be blocked by implementing INewWindowManager interface, additionally code below show how to block alert dialogs by implementing IDocHostShowUI

public class MyBrowser : WebBrowser
{

    [PermissionSetAttribute(SecurityAction.LinkDemand, Name = "FullTrust")]
    public MyBrowser()
    {
    }

    protected override WebBrowserSiteBase CreateWebBrowserSiteBase()
    {
        var manager = new NewWindowManagerWebBrowserSite(this);
        return manager;
    }

    protected class NewWindowManagerWebBrowserSite : WebBrowserSite, IServiceProvider, IDocHostShowUI
    {
        private readonly NewWindowManager _manager;

        public NewWindowManagerWebBrowserSite(WebBrowser host)
            : base(host)
        {
            _manager = new NewWindowManager();
        }

        public int ShowMessage(IntPtr hwnd, string lpstrText, string lpstrCaption, int dwType, string lpstrHelpFile, int dwHelpContext, out int lpResult)
        {
            lpResult = 0;
            return Constants.S_OK; //  S_OK Host displayed its UI. MSHTML does not display its message box.
        }

        // Only files of types .chm and .htm are supported as help files.
        public int ShowHelp(IntPtr hwnd, string pszHelpFile, uint uCommand, uint dwData, POINT ptMouse, object pDispatchObjectHit)
        {
            return Constants.S_OK; //  S_OK Host displayed its UI. MSHTML does not display its message box.
        }

        #region Implementation of IServiceProvider

        public int QueryService(ref Guid guidService, ref Guid riid, out IntPtr ppvObject)
        {
            if ((guidService == Constants.IID_INewWindowManager && riid == Constants.IID_INewWindowManager))
            {
                ppvObject = Marshal.GetComInterfaceForObject(_manager, typeof(INewWindowManager));
                if (ppvObject != IntPtr.Zero)
                {
                    return Constants.S_OK;
                }
            }
            ppvObject = IntPtr.Zero;
            return Constants.E_NOINTERFACE;
        }

        #endregion
    }
 }

[ComVisible(true)]
[Guid("01AFBFE2-CA97-4F72-A0BF-E157038E4118")]
public class NewWindowManager : INewWindowManager
{
    public int EvaluateNewWindow(string pszUrl, string pszName,
        string pszUrlContext, string pszFeatures, bool fReplace, uint dwFlags, uint dwUserActionTime)
    {

        // use E_FAIL to be the same as CoInternetSetFeatureEnabled with FEATURE_WEBOC_POPUPMANAGEMENT
        //int hr = MyBrowser.Constants.E_FAIL; 
        int hr = MyBrowser.Constants.S_FALSE; //Block
        //int hr = MyBrowser.Constants.S_OK; //Allow all
        return hr;
    }
}