this.FormBorderStyle = FormBorderStyle.None;     //设置窗体为无边框样式

            this.WindowState = FormWindowState.Maximized;    //最大化窗体

            this.TopMost = true;                            //设置窗体置顶

        //调用API

        [System.Runtime.InteropServices.DllImport("user32.dll", CharSet = System.Runtime.InteropServices.CharSet.Auto, ExactSpelling = true)]

        public static extern IntPtr GetForegroundWindow(); //获得本窗体的句柄

        [System.Runtime.InteropServices.DllImport("user32.dll", EntryPoint = "SetForegroundWindow")]

        public static extern bool SetForegroundWindow(IntPtr hWnd);//设置此窗体为活动窗体

        //定义变量,句柄类型

        public IntPtr Handle1;

        public Form1()

        {

            InitializeComponent();

        //    this.FormBorderStyle = FormBorderStyle.None;     //设置窗体为无边框样式

          //  this.WindowState = FormWindowState.Maximized;    //最大化窗体

            this.TopMost = true;                            //设置窗体置顶

        }

        private void Form1_Load(object sender, EventArgs e)

        {

            Handle1 = this.Handle;

        }

        private void timer1_Tick(object sender, EventArgs e)

        {

            //设置此窗体为活动窗体

            SetForegroundWindow(Handle1);

        }