[DllImport("user32.dll")]
public static extern int ShowWindow(int hwnd,int nCmdShow);

[DllImport("user32.dll")]
public static extern int FindWindow(string lpClassName,string lpWindowName);

 private const int SW_HIDE = 0;  //隱藏任務欄
        private const int SW_RESTORE = 9;//顯示任務欄

        [DllImport("user32.dll")]
        public static extern int ShowWindow(int hwnd,int nCmdShow);
        [DllImport("user32.dll")]
        public static extern int FindWindow(string lpClassName,string lpWindowName);

        private void button1_Click(object sender, EventArgs e)
        {
            ShowWindow(FindWindow("Shell_TrayWnd",null),SW_HIDE);
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        }

        private void button2_Click(object sender, EventArgs e)
        {

            ShowWindow(FindWindow("Shell_TrayWnd",null),SW_RESTORE);
        }