HwndAppCommandInputProvider.cs source code in C# .NET

Source code for the .NET framework in C#

                        
Code:

                         / DotNET / DotNET / 8.0 / untmp / WIN_WINDOWS / lh_tools_devdiv_wpf / Windows / wcp / Core / System / Windows / InterOp / HwndAppCommandInputProvider.cs / 1 / HwndAppCommandInputProvider.cs
                        

                        
                            using System.Windows.Input; 
using System.Windows.Media;
using System.Windows.Threading;
using System.Diagnostics;
using System.Runtime.InteropServices; 
using System.Security;
using System.Security.Permissions; 
using MS.Utility; 
using MS.Internal;
using MS.Win32; 

namespace System.Windows.Interop
{
    internal sealed class HwndAppCommandInputProvider : DispatcherObject, IInputProvider, IDisposable 
    {
        ///  
        /// Accesses and store critical data. This class is also critical (_site and _source) 
        /// 
        [SecurityCritical] 
        internal HwndAppCommandInputProvider( HwndSource source )
        {
            (new UIPermission(PermissionState.Unrestricted)).Assert();
            try 
            {
                 _site = new SecurityCriticalDataClass(InputManager.Current.RegisterInputProvider(this)); 
            } 
            finally
            { 
                UIPermission.RevertAssert();
            }
            _source = new SecurityCriticalDataClass(source);
        } 

        ///  
        /// Critical:This class accesses critical data, _site. 
        /// TreatAsSafe: This class does not expose the critical data
        ///  
        [SecurityCritical, SecurityTreatAsSafe]
        public void Dispose( )
        {
            if (_site != null) 
            {
                _site.Value.Dispose(); 
                _site = null; 
            }
            _source = null; 
        }

        /// 
        /// Critical: As this accesses critical data HwndSource 
        /// TreatAsSafe:Information about whether a given input provider services
        /// a visual is safe to expose. This method does not expose the critical data either. 
        ///  
        [SecurityCritical, SecurityTreatAsSafe]
        bool IInputProvider.ProvidesInputForRootVisual( Visual v ) 
        {
            Debug.Assert(null != _source);
            return _source.Value.RootVisual == v;
        } 

        void IInputProvider.NotifyDeactivate() {} 
 
        /// 
        /// Critical: As this accesses critical data HwndSource 
        /// 
        [SecurityCritical]
        internal IntPtr FilterMessage( IntPtr hwnd, int msg, IntPtr wParam, IntPtr lParam, ref bool handled )
        { 
            // It is possible to be re-entered during disposal.  Just return.
            if(null == _source || null == _source.Value) 
            { 
                return IntPtr.Zero;
            } 

            if (msg == NativeMethods.WM_APPCOMMAND)
            {
                // WM_APPCOMMAND message notifies a window that the user generated an application command event, 
                // for example, by clicking an application command button using the mouse or typing an application command
                // key on the keyboard. 
                RawAppCommandInputReport report = new RawAppCommandInputReport( 
                                                        _source.Value,
                                                        InputMode.Foreground, 
                                                        SafeNativeMethods.GetMessageTime(),
                                                        GetAppCommand(lParam),
                                                        GetDevice(lParam),
                                                        InputType.Command); 

                handled = _site.Value.ReportInput(report); 
            } 

            return handled ? new IntPtr(1) : IntPtr.Zero ; 
        }

        /// 
        /// Implementation of the GET_APPCOMMAND_LPARAM macro defined in Winuser.h 
        /// 
        ///  
        ///  
        private static int GetAppCommand( IntPtr lParam )
        { 
            return ((short)(NativeMethods.SignedHIWORD(NativeMethods.IntPtrToInt32(lParam)) & ~NativeMethods.FAPPCOMMAND_MASK));
        }

        ///  
        /// Returns the input device that originated this app command.
        /// InputType.Hid represents an unspecified device that is neither the 
        /// keyboard nor the mouse. 
        /// 
        ///  
        /// 
        private static InputType GetDevice(IntPtr lParam)
        {
            InputType inputType = InputType.Hid; 

            // Implementation of the GET_DEVICE_LPARAM macro defined in Winuser.h 
            // Returns either FAPPCOMMAND_KEY (the user pressed a key), FAPPCOMMAND_MOUSE 
            // (the user clicked a mouse button) or FAPPCOMMAND_OEM (unknown device)
            ushort  deviceId = (ushort)(NativeMethods.SignedHIWORD(NativeMethods.IntPtrToInt32(lParam)) & NativeMethods.FAPPCOMMAND_MASK); 

            switch (deviceId)
            {
                case NativeMethods.FAPPCOMMAND_MOUSE: 
                    inputType = InputType.Mouse;
                    break; 
 
                case NativeMethods.FAPPCOMMAND_KEY:
                    inputType =  InputType.Keyboard; 
                    break;

                case NativeMethods.FAPPCOMMAND_OEM:
                default: 
                    // Unknown device id or FAPPCOMMAND_OEM.
                    // In either cases we set it to the generic human interface device. 
                    inputType=InputType.Hid; 
                    break;
            } 

            return inputType;
        }
 
        /// 
        /// This is got under an elevation and is hence critical. This data is not ok to expose. 
        ///  
        private SecurityCriticalDataClass _source;
 
        /// 
        /// This is got under an elevation and is hence critical.This data is not ok to expose.
        /// 
        private SecurityCriticalDataClass _site; 
    }
} 
 


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

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