windows程序里新窗体不在任务栏显示，无标题拖动，键盘事件，始终显示在主窗体上面，单实例运行等

        protected override CreateParams CreateParams        {            get            {                const int WS_EX_APPWINDOW = 0x40000;                const int WS_EX_TOOLWINDOW = 0x80;                CreateParams cp = base.CreateParams;                cp.ExStyle &= (~WS_EX_APPWINDOW);    // 不显示在TaskBar                cp.ExStyle |= WS_EX_TOOLWINDOW;      // 不显示在Alt-Tab                return cp;            }        }

        [DllImport("user32.dll")]        public static extern bool ReleaseCapture();        [DllImport("user32.dll")]        public static extern bool SendMessage(IntPtr hwnd, int wMsg, int wParam, int lParam);        public const int SC_MOVE = 0xF010;        public const int HTCAPTION = 0x0002;        public const Int32 WM_SYSCOMMAND = 274;        private void picMain_MouseDown(object sender, MouseEventArgs e)        {            ReleaseCapture();            SendMessage(this.Handle, WM_SYSCOMMAND, SC_MOVE + HTCAPTION, 0);        }

        protected override bool ProcessCmdKey(ref Message msg, Keys keyData)        {            int WM_KEYDOWN = 256;            int WM_SYSKEYDOWN = 260;            if (msg.Msg == WM_KEYDOWN | msg.Msg == WM_SYSKEYDOWN)            {                switch (keyData)                {                    case Keys.Escape:                        this.WindowState = FormWindowState.Normal;                        return false;                    case Keys.Enter:                        this.WindowState = FormWindowState.Maximized;                        return false;                    case Keys.Up:                    case Keys.Left:                        return false;                    case Keys.Right:                    case Keys.Down:                        return false;                }            }            return base.ProcessCmdKey(ref msg, keyData);        }

        [DllImport("user32 ")]        public static extern IntPtr SetParent(IntPtr hWndChild, IntPtr hWndNewParent);            Form frm = new Form();            SetParent(frm.Handle, this.Handle);

检测是否有实例

            bool createNew;            using (System.Threading.Mutex m = new System.Threading.Mutex(true, "Global\\" + Application.ProductName, out createNew))            {                if (createNew)                {/// 执行创建工作} else                {                    /// 激活现有实例                }            }

        [DllImport("user32.dll")]        public static extern bool IsIconic(IntPtr hWnd);        //隐藏窗口，活动状态给令一个窗口        private const int SW_HIDE = 0;        //用原来的大小和位置显示一个窗口，同时令其进入活动状态        private const int SW_SHOWNORMAL = 1;        //最小化窗口，并将其激活        private const int SW_SHOWMINIMIZED = 2;        //最大化窗口，并将其激活        private const int SW_SHOWMAXIMIZED = 3;        //用最近的大小和位置显示一个窗口，同时不改变活动窗口        private const int SW_SHOWNOACTIVATE = 4;        //用原来的大小和位置显示一个窗口，同时令其进入活动状态        private const int SW_RESTORE = 9;        //根据默认 创建窗口时的样式 来显示        private const int SW_SHOWDEFAULT = 10;        [DllImport("User32.dll")]        public static extern bool ShowWindowAsync(System.IntPtr hWnd, int cmdShow);        [DllImport("User32.dll")]        public static extern bool SetForegroundWindow(System.IntPtr hWnd);        public static void RaiseOtherProcess()        {            Process proc = Process.GetCurrentProcess();            Process.GetProcesses();            foreach (Process otherProc in                Process.GetProcessesByName(Process.GetCurrentProcess().ProcessName))            {                if (proc.Id != otherProc.Id)                {                    IntPtr hWnd = otherProc.MainWindowHandle;                    if (IsIconic(hWnd))                    {                        ShowWindowAsync(hWnd, SW_RESTORE);                    }                    SetForegroundWindow(hWnd);                    break;                }            }        }