Set window always on top from a tray icon in C#

/*
 *
 * Developed by Adam Rakaska
 *  http://csharpcodewhisperer.blogspot.com
 *    http://arakaska.wix.com/intelligentsoftware
 *
 *
 * Made using SharpDevelop
 *
 *
 */
using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Drawing;
using System.Globalization;
using System.Runtime.InteropServices;
using System.Threading;
using System.Windows.Forms;

namespace StayOnTop
{
    public sealed class NotificationIcon
    {
        // Changelog; stores a list of windows we made topmost,
        //  so we can 'roll-back' the changes upon exit.
        //
        // ChangeLog<WindowTitle, IsTopmost>
        private Dictionary<string,bool> changeLog = new Dictionary<string, bool>();

        // Performance / use information. Shown in the about box.
        int numRedraws      = 0;

        private NotifyIcon notifyIcon;
        public NotificationIcon()
        {
            // Initialize
            notifyIcon = new NotifyIcon();
            notifyIcon.ContextMenu = new ContextMenu();

            // Subscribe to events
            notifyIcon.ContextMenu.Popup    += menuDrawMenu;    // DoubleClick, MouseDown

            // Resources
            System.ComponentModel.ComponentResourceManager resources = new System.ComponentModel.ComponentResourceManager(typeof(NotificationIcon));
            notifyIcon.Icon = (Icon)resources.GetObject("$this.Icon");
        }

        // The icon has been clicked, the menu is about to be drawn
        private void menuDrawMenu(object sender, EventArgs e)
        {
            numRedraws++;
            notifyIcon.ContextMenu.MenuItems.Clear();
            notifyIcon.ContextMenu.MenuItems.AddRange(DynamicMenu());
        }

        // Generate a context menu that displays titles of windows
        private MenuItem[] DynamicMenu()
        {
            string[] titleArray = GetWindowTitles();

            List<MenuItem> menuList = new List<MenuItem>();
            foreach(string title in titleArray)
            {
                if(changeLog.ContainsKey(title))
                {
                    if(changeLog[title])
                    {
                        menuList.Add(new MenuItem("* " + title, menuWinClick));
                    }
                    else
                    {
                        menuList.Add(new MenuItem(title, menuWinClick));
                    }
                }
                else
                {
                    menuList.Add(new MenuItem(title, menuWinClick));
                }
            }
            menuList.Add(new MenuItem("_____________"));
            menuList.Add(new MenuItem("About", menuAboutClick));
            menuList.Add(new MenuItem("Exit", menuExitClick));

            return menuList.ToArray();
        }


        private void menuWinClick(object sender, EventArgs e)
        {
            string title = sender.ToString();

            string[] winTitles = GetWindowTitles();
            foreach(string win in winTitles)
            {
                if(title.Contains(win))
                {
                    title = win;
                }
            }

            if(changeLog.ContainsKey(title))
            {
                bool isTopmost = !changeLog[title];
                changeLog[title] = isTopmost;
                AssignTopmostWindow(title,isTopmost);
            }
            else
            {
                changeLog.Add(title,true);
                AssignTopmostWindow(title,true);
            }
        }

        private void menuExitClick(object sender, EventArgs e)
        {
            // Roll-back changes by
            //  unsetting every topmost window
            foreach(KeyValuePair<string,bool> entry in changeLog)
            {
                if(entry.Value) // If topmost
                {
                    AssignTopmostWindow(entry.Key,false);
                }
            }

            Application.Exit();
        }

        private void menuAboutClick(object sender, EventArgs e)
        {
            MessageBox.Show(string.Join(Environment.NewLine,
                                        "TopmostTray - Makes windows always on top",
                                        "  by Adam Rakaska",
                                        "    http://csharpcodewhisperer.blogspot.com",
                                        "",
                                        "Number of menu redraws: " + numRedraws.ToString()
                                       ),
                            "About"
                           );
        }

        string[] GetWindowTitles()
        {
            List<string> winList = new List<string>();

            Process[] procArray = Process.GetProcesses();
            foreach(Process proc in procArray)
            {
                if(!string.IsNullOrWhiteSpace(proc.MainWindowTitle))
                {
                    winList.Add(proc.MainWindowTitle);
                }
            }
            return winList.ToArray();
        }

        void AssignTopmostWindow(string windowTitle,bool makeTopmost)
        {
            IntPtr hWnd = FindWindow((string)null,windowTitle);

            RECT rect = new RECT();
            GetWindowRect(new HandleRef(this,hWnd),out rect);

            SetWindowPos(hWnd,
                         makeTopmost ? HWND_TOPMOST : HWND_NOTOPMOST,
                         rect.X, rect.Y, rect.Width, rect.Height,
                         SWP_SHOWWINDOW);
        }



        #region Main

        [STAThread]
        public static void Main(string[] args)
        {
            Application.EnableVisualStyles();
            Application.SetCompatibleTextRenderingDefault(false);

            bool isFirstInstance;
            // Please use a unique name for the mutex to prevent conflicts with other programs
            using (Mutex mtx = new Mutex(true, "TopmostTray", out isFirstInstance))
            {
                if (isFirstInstance) {
                    NotificationIcon notificationIcon = new NotificationIcon();
                    notificationIcon.notifyIcon.Visible = true;
                    Application.Run();
                    notificationIcon.notifyIcon.Dispose();
                } else {
                    // The application is already running
                    // TODO: Display message box or change focus to existing application instance
                }
            } // releases the Mutex
        }

        #endregion



        #region WIN32

        static readonly IntPtr HWND_TOPMOST = new IntPtr(-1);
        static readonly IntPtr HWND_NOTOPMOST = new IntPtr(-2);
        static readonly IntPtr HWND_TOP = new IntPtr(0);
        static readonly IntPtr HWND_BOTTOM = new IntPtr(1);
        const UInt32 SWP_NOSIZE = 0x0001;
        const UInt32 SWP_NOMOVE = 0x0002;
        const UInt32 SWP_NOZORDER = 0x0004;
        const UInt32 SWP_NOREDRAW = 0x0008;
        const UInt32 SWP_NOACTIVATE = 0x0010;
        const UInt32 SWP_FRAMECHANGED = 0x0020;
        const UInt32 SWP_SHOWWINDOW = 0x0040;
        const UInt32 SWP_HIDEWINDOW = 0x0080;
        const UInt32 SWP_NOCOPYBITS = 0x0100;
        const UInt32 SWP_NOOWNERZORDER = 0x0200;
        const UInt32 SWP_NOSENDCHANGING = 0x0400;

        [StructLayout(LayoutKind.Sequential)]
        public struct RECT
        {
            public int Left, Top, Right, Bottom;
            public RECT(int left, int top, int right, int bottom) { Left = left; Top = top; Right = right; Bottom = bottom; }
            public RECT(System.Drawing.Rectangle r) : this(r.Left, r.Top, r.Right, r.Bottom) { }
            public int X { get { return Left; } set { Right -= (Left - value); Left = value; } }
            public int Y { get { return Top; } set { Bottom -= (Top - value); Top = value; } }
            public int Height { get { return Bottom - Top; } set { Bottom = value + Top; } }
            public int Width { get { return Right - Left; } set { Right = value + Left; } }
            public static implicit operator System.Drawing.Rectangle(RECT r) { return new System.Drawing.Rectangle(r.Left, r.Top, r.Width, r.Height); }
            public static implicit operator RECT(System.Drawing.Rectangle r) { return new RECT(r); }
        }

        [DllImport("user32.dll", SetLastError = true)]
        private static extern IntPtr FindWindow(String lpClassName, String lpWindowName);

        [DllImport("user32.dll")]
        [return: MarshalAs(UnmanagedType.Bool)]
        public static extern bool GetWindowRect(HandleRef hwnd, out RECT lpRect);

        [DllImport("user32.dll")]
        [return: MarshalAs(UnmanagedType.Bool)]
        private static extern bool SetWindowPos( IntPtr hWnd, IntPtr hWndInsertAfter,
                                                int x, int y, int cx, int cy,
                                                uint uFlags
                                               );

        #endregion

    }
}