Запретить звуковой сигнал при загрузке в Winforms управления WebBrowser

Попробуйте создать свой собственный элемент управления WebBrowser, как показано ниже. SafeWebBrowser - это управляемый WebBrowser элемент управления, который НЕ позволяет запускать скрипты или элементы управления ActiveX. Он также запрещает отображение контекстного меню WebBrowser. Не уверен, что это остановит звуковой сигнал, но попробуй.

using System;
using System.Collections.Generic;
using System.Globalization;
using System.Reflection;
using System.Runtime.InteropServices;
using System.Windows.Forms;

/// <summary>
/// Stole code from http://stackoverflow.com/questions/7608550/implement-idispatchinvoke-to-be-called-by-a-webbrowser-control
/// </summary>
public class SafeWebBrowser : WebBrowser
{
    private const int DISPID_AMBIENT_DLCONTROL = -5512;
    private int _downloadControlFlags;

    protected override void OnHandleCreated( EventArgs e )
    {
        base.OnHandleCreated( e );

        // Here is where the magic happens.
        // Disable java, scripts, activeX controls, etc.
        //

        DownloadControlFlags = ( int )(
            WebBrowserDownloadControlFlags.NO_JAVA
            | WebBrowserDownloadControlFlags.NO_BEHAVIORS
            | WebBrowserDownloadControlFlags.NO_DLACTIVEXCTLS
            | WebBrowserDownloadControlFlags.NO_RUNACTIVEXCTLS
            | WebBrowserDownloadControlFlags.NO_SCRIPTS
            | WebBrowserDownloadControlFlags.PRAGMA_NO_CACHE
            | WebBrowserDownloadControlFlags.SILENT
            | WebBrowserDownloadControlFlags.DLIMAGES
        );

        // Disable the context menu.
        //

        this.IsWebBrowserContextMenuEnabled = false;
    }

    // we want our site class, not the default one
    protected override WebBrowserSiteBase CreateWebBrowserSiteBase()
    {
        return new MyWebBrowserSite( this );
    }

    [DispId( DISPID_AMBIENT_DLCONTROL )]
    private int DownloadControlFlags
    {
        get
        {
            return _downloadControlFlags;
        }
        set
        {
            if ( _downloadControlFlags == value )
                return;

            _downloadControlFlags = value;
            IOleControl ctl = ( IOleControl )ActiveXInstance;
            ctl.OnAmbientPropertyChange( DISPID_AMBIENT_DLCONTROL );
        }
    }

    private class MyWebBrowserSite : WebBrowserSite, IReflect
    {
        private Dictionary<int, PropertyInfo> _dispidCache;
        private SafeWebBrowser _host;

        public MyWebBrowserSite( SafeWebBrowser host )
            : base( host )
        {
            _host = host;
        }

        object IReflect.InvokeMember( string name, BindingFlags invokeAttr, Binder binder, object target, object[] args, ParameterModifier[] modifiers, CultureInfo culture, string[] namedParameters )
        {
            object ret = null;
            // Check direct IDispatch call using a dispid (see http://msdn.microsoft.com/en-us/library/de3dhzwy.aspx)
            const string dispidToken = "[DISPID=";
            if ( name.StartsWith( dispidToken ) )
            {
                int dispid = int.Parse( name.Substring( dispidToken.Length, name.Length - dispidToken.Length - 1 ) );
                if ( _dispidCache == null )
                {
                    // WebBrowser has many properties, so we build a dispid cache on it
                    _dispidCache = new Dictionary<int, PropertyInfo>();
                    foreach ( PropertyInfo pi in _host.GetType().GetProperties( BindingFlags.Public | BindingFlags.Instance ) )
                    {
                        if ( ( !pi.CanRead ) || ( pi.GetIndexParameters().Length > 0 ) )
                            continue;

                        object[] atts = pi.GetCustomAttributes( typeof( DispIdAttribute ), true );
                        if ( ( atts != null ) && ( atts.Length > 0 ) )
                        {
                            DispIdAttribute da = ( DispIdAttribute )atts[ 0 ];
                            _dispidCache[ da.Value ] = pi;
                        }
                    }
                }

                PropertyInfo property;
                if ( _dispidCache.TryGetValue( dispid, out property ) )
                {
                    ret = property.GetValue( _host, null );
                }
            }
            return ret;
        }

        FieldInfo[] IReflect.GetFields( BindingFlags bindingAttr )
        {
            return GetType().GetFields( bindingAttr );
        }

        MethodInfo[] IReflect.GetMethods( BindingFlags bindingAttr )
        {
            return GetType().GetMethods( bindingAttr );
        }

        PropertyInfo[] IReflect.GetProperties( BindingFlags bindingAttr )
        {
            return GetType().GetProperties( bindingAttr );
        }

        FieldInfo IReflect.GetField( string name, BindingFlags bindingAttr )
        {
            throw new NotImplementedException();
        }

        MemberInfo[] IReflect.GetMember( string name, BindingFlags bindingAttr )
        {
            throw new NotImplementedException();
        }

        MemberInfo[] IReflect.GetMembers( BindingFlags bindingAttr )
        {
            throw new NotImplementedException();
        }

        MethodInfo IReflect.GetMethod( string name, BindingFlags bindingAttr )
        {
            throw new NotImplementedException();
        }

        MethodInfo IReflect.GetMethod( string name, BindingFlags bindingAttr, Binder binder, Type[] types, ParameterModifier[] modifiers )
        {
            throw new NotImplementedException();
        }

        PropertyInfo IReflect.GetProperty( string name, BindingFlags bindingAttr, Binder binder, Type returnType, Type[] types, ParameterModifier[] modifiers )
        {
            throw new NotImplementedException();
        }

        PropertyInfo IReflect.GetProperty( string name, BindingFlags bindingAttr )
        {
            throw new NotImplementedException();
        }

        Type IReflect.UnderlyingSystemType
        {
            get { throw new NotImplementedException(); }
        }
    }

    [ComImport, InterfaceType( ComInterfaceType.InterfaceIsIUnknown ), Guid( "B196B288-BAB4-101A-B69C-00AA00341D07" )]
    private interface IOleControl
    {
        void Reserved0();
        void Reserved1();
        void OnAmbientPropertyChange( int dispID );
        void Reserved2();
    }

    [Flags]
    enum WebBrowserDownloadControlFlags : uint
    {
        DLIMAGES = 0x00000010,
        VIDEOS = 0x00000020,
        BGSOUNDS = 0x00000040,
        NO_SCRIPTS = 0x00000080,
        NO_JAVA = 0x00000100,
        NO_RUNACTIVEXCTLS = 0x00000200,
        NO_DLACTIVEXCTLS = 0x00000400,
        DOWNLOADONLY = 0x00000800,
        NO_FRAMEDOWNLOAD = 0x00001000,
        RESYNCHRONIZE = 0x00002000,
        PRAGMA_NO_CACHE = 0x00004000,
        NO_BEHAVIORS = 0x00008000,
        NO_METACHARSET = 0x00010000,
        URL_ENCODING_DISABLE_UTF8 = 0x00020000,
        URL_ENCODING_ENABLE_UTF8 = 0x00040000,
        NOFRAMES = 0x00080000,
        FORCEOFFLINE = 0x10000000,
        NO_CLIENTPULL = 0x20000000,
        SILENT = 0x40000000,
        OFFLINEIFNOTCONNECTED = 0x80000000,
        OFFLINE = OFFLINEIFNOTCONNECTED,
    }
}