Processing Global Mouse and Keyboard Hooks in C#

using System.Runtime.InteropServices;

namespace Gma.UserActivityMonitor {

    public static partial class HookManager {
        /// <summary>
        /// The Point structure defines the X- and Y- coordinates of a point. 
        /// </summary>
        /// <remarks>
        /// http://msdn.microsoft.com/library/default.asp?url=/library/en-us/gdi/rectangl_0tiq.asp
        /// </remarks>
        [StructLayout(LayoutKind.Sequential)]
        private struct Point {
            /// <summary>
            /// Specifies the X-coordinate of the point. 
            /// </summary>
            public int X;
            /// <summary>
            /// Specifies the Y-coordinate of the point. 
            /// </summary>
            public int Y;
        }

        /// <summary>
        /// The MSLLHOOKSTRUCT structure contains information about a low-level keyboard input event. 
        /// </summary>
        [StructLayout(LayoutKind.Sequential)]
        private struct MouseLLHookStruct {
            /// <summary>
            /// Specifies a Point structure that contains the X- and Y-coordinates of the cursor, in screen coordinates. 
            /// </summary>
            public Point Point;
            /// <summary>
            /// If the message is WM_MOUSEWHEEL, the high-order word of this member is the wheel delta. 
            /// The low-order word is reserved. A positive value indicates that the wheel was rotated forward, 
            /// away from the user; a negative value indicates that the wheel was rotated backward, toward the user. 
            /// One wheel click is defined as WHEEL_DELTA, which is 120. 
            ///If the message is WM_XBUTTONDOWN, WM_XBUTTONUP, WM_XBUTTONDBLCLK, WM_NCXBUTTONDOWN, WM_NCXBUTTONUP,
            /// or WM_NCXBUTTONDBLCLK, the high-order word specifies which X button was pressed or released, 
            /// and the low-order word is reserved. This value can be one or more of the following values. Otherwise, MouseData is not used. 
            ///XBUTTON1
            ///The first X button was pressed or released.
            ///XBUTTON2
            ///The second X button was pressed or released.
            /// </summary>
            public int MouseData;
            /// <summary>
            /// Specifies the event-injected flag. An application can use the following value to test the mouse Flags. Value Purpose 
            ///LLMHF_INJECTED Test the event-injected flag.  
            ///0
            ///Specifies whether the event was injected. The value is 1 if the event was injected; otherwise, it is 0.
            ///1-15
            ///Reserved.
            /// </summary>
            public int Flags;
            /// <summary>
            /// Specifies the Time stamp for this message.
            /// </summary>
            public int Time;
            /// <summary>
            /// Specifies extra information associated with the message. 
            /// </summary>
            public int ExtraInfo;
        }

        /// <summary>
        /// The KBDLLHOOKSTRUCT structure contains information about a low-level keyboard input event. 
        /// </summary>
        /// <remarks>
        /// http://msdn.microsoft.com/library/default.asp?url=/library/en-us/winui/winui/windowsuserinterface/windowing/hooks/hookreference/hookstructures/cwpstruct.asp
        /// </remarks>
        [StructLayout(LayoutKind.Sequential)]
        private struct KeyboardHookStruct
        {
            /// <summary>
            /// Specifies a virtual-key code. The code must be a value in the range 1 to 254. 
            /// </summary>
            public int VirtualKeyCode;
            /// <summary>
            /// Specifies a hardware scan code for the key. 
            /// </summary>
            public int ScanCode;
            /// <summary>
            /// Specifies the extended-key flag, event-injected flag, context code, and transition-state flag.
            /// </summary>
            public int Flags;
            /// <summary>
            /// Specifies the Time stamp for this message.
            /// </summary>
            public int Time;
            /// <summary>
            /// Specifies extra information associated with the message. 
            /// </summary>
            public int ExtraInfo;
        }
    }
}