private void PrintService_SizeChanged(object sender, EventArgs e)        {            if (this.WindowState == FormWindowState.Minimized)            {                this.Hide();                this.notifyIcon.Visible = true;            }        }        private void PrintService_FormClosing(object sender, FormClosingEventArgs e)        {            if (MessageBox.Show("是否关闭服务", "确认", MessageBoxButtons.YesNo, MessageBoxIcon.Question) == System.Windows.Forms.DialogResult.No)                e.Cancel = true;        }        private void 退出ToolStripMenuItem_Click(object sender, EventArgs e)        {            if (MessageBox.Show("是否确认退出程序？", "退出", MessageBoxButtons.OKCancel, MessageBoxIcon.Question) == DialogResult.OK)            {                // 关闭所有的线程                this.Dispose();                this.Close();            }        }        private void 显示ToolStripMenuItem_Click(object sender, EventArgs e)        {            if (this.WindowState == FormWindowState.Minimized)            {                this.Show();                this.ShowInTaskbar = true;                this.WindowState = FormWindowState.Normal;                notifyIcon.Visible = false;            }        }

参考：http://www.cnblogs.com/nangong/p/997995dc3743b60baac30899c3d82ef7.html

http://www.cnblogs.com/_zjl/archive/2011/05/16/2047918.html             WinForm中实现最小化到系统托盘

http://www.cnblogs.com/xugang/archive/2007/12/19/1006005.html      C#实现WinForm窗口最小化到系统托盘