BrowserInteropHelper.cs source code in C# .NET

                        Code:
                         / DotNET / DotNET / 8.0 / untmp / WIN_WINDOWS / lh_tools_devdiv_wpf / Windows / wcp / Framework / System / Windows / Interop / BrowserInteropHelper.cs / 1 / BrowserInteropHelper.cs
                        
                        
                            //---------------------------------------------------------------------------- 
//
// File: BrowserInteropHelper.cs
//
// Description: Implements Avalon BrowserInteropHelper class, which helps 
//              interop with the browser
// 
// Created: 08/02/05 
//
// Copyright (C) by Microsoft Corporation.  All rights reserved. 
//
//---------------------------------------------------------------------------

using System; 
using System.Runtime.InteropServices;
using System.Windows; 
using System.Windows.Interop; 
using System.Windows.Threading;
using System.Security; 
using System.Security.Permissions;
using System.Diagnostics;
using MS.Internal;
using MS.Internal.PresentationFramework;                   // SecurityHelper 
using MS.Win32;
using System.Windows.Input; 
using MS.Internal.AppModel; 

namespace System.Windows.Interop 
{
    /// 
    /// Implements Avalon BrowserInteropHelper, which helps interop with the browser
    ///  
    public static class BrowserInteropHelper
    { 
        ///  
        /// Critical because it sets critical data.
        /// Safe because it is the static ctor, and the data doesn't go anywhere. 
        /// 
        [SecurityCritical, SecurityTreatAsSafe]
        static BrowserInteropHelper()
        { 
            SetBrowserHosted(false);
            IsViewer = false; 
            IsInitialViewerNavigation = true; 
        }
 
        /// 
        /// Returns the IOleClientSite interface
        /// 
        ///  
        ///     Callers must have UnmanagedCode permission to call this API.
        ///  
        ///  
        ///   Critical: Exposes a COM interface pointer to the IOleClientSite where the app is hosted
        ///   PublicOK: It is public, but there is a demand 
        /// 
        public static object ClientSite
        {
            [SecurityCritical] 
            get
            { 
                SecurityHelper.DemandUnmanagedCode(); 

                object oleClientSite = null; 

                if (IsBrowserHosted)
                {
                    Application.Current.BrowserCallbackServices.GetOleClientSite(out oleClientSite); 
                }
 
                return oleClientSite; 
            }
        } 

        /// 
        /// Returns true if the app is a browser hosted app.
        ///  
        public static bool IsBrowserHosted
        { 
            get 
            {
                return _isBrowserHosted.Value; 
            }
        }

        ///  
        /// This is critical because setting the BrowserHosted status is a critical resource.
        ///  
        [SecurityCritical] 
        internal static void SetBrowserHosted(bool value)
        { 
            _isBrowserHosted.Value = value;
        }

 
        /// 
        /// Returns the Uri used to launch the application. 
        ///  
        public static Uri Source
        { 
            get
            {
                return _source.Value;
            } 
        }
 
        ///  
        /// Sets the Source URI
        ///  
        /// 
        /// Critical: critical because setting the source is critical.
        /// 
        [SecurityCritical] 
        internal static void SetSource(Uri source)
        { 
            _source.Value = source; 
        }
 
        /// 
        /// Returns true if the app is a viewer app.
        /// 
        ///  
        /// Critical: critical because setting the viewer status is a critical resource.
        ///  
        internal static bool IsViewer 
        {
            get 
            {
                return _isViewer.Value;
            }
            [SecurityCritical] 
            set
            { 
                _isViewer.Value = value; 
            }
        } 

        /// 
        /// Returns true if avalon it top level.
        /// Also returns true if not browser-hosted. 
        /// 
        ///  
        /// Critical: Calls the SUCd IBrowserCallbackServices.IsAvalonTopLevel(). 
        /// Safe: This is okay to dislose.
        ///  
        internal static bool IsAvalonTopLevel
        {
            [SecurityCritical, SecurityTreatAsSafe]
            get 
            {
                if (!IsBrowserHosted) 
                    return true; 
                IBrowserCallbackServices bcs = Application.Current.BrowserCallbackServices;
                return bcs != null && bcs.IsAvalonTopLevel(); 
            }
        }

        ///  
        /// Returns true if we are in viewer mode AND this is the first time that a viewer has been navigated.
        /// Including IsViewer is defense-in-depth in case somebody forgets to check IsViewer. There are other 
        /// reasons why both IsViewer and IsViewerNavigation are necessary, however. 
        /// 
        ///  
        /// Critical: setting this information is a critical resource.
        /// 
        internal static bool IsInitialViewerNavigation
        { 
            get
            { 
                return IsViewer && _isInitialViewerNavigation.Value; 
            }
            [SecurityCritical] 
            set
            {
                _isInitialViewerNavigation.Value = value;
            } 
        }
 
        ///  
        ///     Critical: this calls ForwardTranslateAccelerator, which is SUC'ed.
        ///  
        [SecurityCritical]
        private static void HostFilterInput(ref MSG msg, ref bool handled)
        {
            // The host gets to see input, keyboard and mouse messages. 
            if (msg.message == MS.Win32.NativeMethods.WM_INPUT ||
                (msg.message >= MS.Win32.NativeMethods.WM_KEYFIRST && msg.message <= MS.Win32.NativeMethods.WM_IME_KEYLAST) || 
                (msg.message >= MS.Win32.NativeMethods.WM_MOUSEFIRST && msg.message <= MS.Win32.NativeMethods.WM_MOUSELAST)) 
            {
                if (MS.Win32.NativeMethods.S_OK == ForwardTranslateAccelerator(ref msg, false)) 
                {
                    handled = true;
                }
            } 
        }
 
        ///  This hook gets a "last chance" to handle a key. Such applicaton-unhandled 
        /// keys are forwarded to the browser frame.
        ///  
        /// 
        ///     Critical: this calls ForwardTranslateAccelerator, which is SUC'ed.
        /// 
        [SecurityCritical] 
        internal static IntPtr PostFilterInput(IntPtr hwnd, int msg, IntPtr wParam, IntPtr lParam, ref bool handled)
        { 
            if (!handled) 
            {
                if (msg >= MS.Win32.NativeMethods.WM_KEYFIRST && msg <= MS.Win32.NativeMethods.WM_IME_KEYLAST) 
                {
                    MSG m = new MSG(hwnd, msg, wParam, lParam, SafeNativeMethods.GetMessageTime(), 0, 0);
                    if (MS.Win32.NativeMethods.S_OK == ForwardTranslateAccelerator(ref m, true))
                    { 
                        handled = true;
                    } 
                } 
            }
            return IntPtr.Zero; 
        }

        /// 
        ///     Critical: this attaches an event to ThreadFilterMessage, which requires an assert 
        ///     Safe: doesn't expose anything, just does some internal plumbing stuff
        ///  
        [SecurityCritical, SecurityTreatAsSafe] 
        internal static void InitializeHostFilterInput()
        { 
            (new UIPermission(PermissionState.Unrestricted)).Assert(); // Blessed assert
            try
            {
                ComponentDispatcher.ThreadFilterMessage += 
                                    new ThreadMessageEventHandler(HostFilterInput);
            } 
            finally 
            {
                UIPermission.RevertAssert(); 
            }

        }
 
        private static SecurityCriticalDataForSet _isBrowserHosted;
 
        private static SecurityCriticalDataForSet _isViewer; 

        private static SecurityCriticalDataForSet _isInitialViewerNavigation; 

        private static SecurityCriticalDataForSet _source;

        /// 
        ///     Critical - call is SUC'ed
        /// 
        [SecurityCritical, SuppressUnmanagedCodeSecurity] 
        [DllImport("PresentationHostDLL.dll", EntryPoint = "ForwardTranslateAccelerator")]
        private static extern int ForwardTranslateAccelerator(ref MSG pMsg, bool appUnhandled); 
    }
}


// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.
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