程序自动锁屏机制实现

this.loadPath();
            LockMsg.PreTime = DateTime.Now;
            this.lookCount.Enabled = true;
            this.lookCount.Interval = 1000;
            this.lookCount.Tick += new EventHandler(this.lookCount_Tick);
            LockMsg lm = new LockMsg();
            Application.AddMessageFilter(lm);

            this.Activated += new EventHandler(FrmMainOrLeaveFrm_Activated);
            this.Deactivate += new EventHandler(FrmMainOrLeaveFrm_Deactivate);


 private Timer lookCount = new Timer();       

        /// <summary>
        /// 
        /// </summary>
        private void setDiffDate(DateTime nowTime,object sender, EventArgs e)
        {
            if (!LockMsg.LockState)
            {
                TimeSpan spaceTime = nowTime - LockMsg.PreTime;
                double spaceMinutes = spaceTime.TotalMinutes;
                foreach (Form form in Application.OpenForms)
                {
                    if (!form.Name.Equals("FrmMain") && form.TopLevel)
                    {

                        form.Deactivate += new EventHandler(this.FrmMainOrLeaveFrm_Deactivate);
                        form.Activated += new EventHandler(this.FrmMainOrLeaveFrm_Activated);                        
                    }
                }

                if (!LockMsg.UseState)
                {
                    if (spaceMinutes > LockMsg.LockSpace)
                    {
                        LockMsg.LockState = true;//锁定
                       // this.Select();  //行2  //this.Activate(); //行 2  //this.Focus(); 行 1 // this.BringToFront();  行 2 
                        this.Activate(); 
                                     
                        foreach (Form f in Application.OpenForms)
                        {
                            f.Enabled = false;
                        }
                        
                        FrmLock frmLock = new FrmLock();//锁定界面  
                        frmLock.LockOrSet = true;                        
                        frmLock.ShowDialog();                       
                    }
                }
                else if (LockMsg.UseState)
                {                    
                    foreach (Form form in Application.OpenForms)
                    {
                        if (form.Name.Equals("FrmMain") && form.TopLevel)
                        {
                            LockMsg.NowPoint = form.PointToClient(Control.MousePosition);