C# 最小化到托盘 双击托盘恢复

1.添加notifyIcon控件，并添加Icon，否则托盘没有图标（托盘右键菜单也可直接在属性里添加）；
2.响应Form的Resize或SizeChanged消息：

        // Hide to system tray
        private void Form1_Resize(object sender, EventArgs e)
        {
            if (this.WindowState == FormWindowState.Minimized)
            {
                this.Hide();
                this.ShowInTaskbar = false;
                this.notifyIcon.Visible = true;
            }
        }

3.双击托盘图标恢复需要响应notifyIcon的DoubleClick消息：

        // Show from system tray
        private void notifyIcon_DoubleClick(object sender, EventArgs e)
        {
            if (this.WindowState == FormWindowState.Minimized)
            {
                this.Show();
                this.WindowState = FormWindowState.Normal;
                notifyIcon.Visible = false;
                this.ShowInTaskbar = true;
            }
        }