WinForm窗口最小化到系统托盘

1. 在Form上加notifyicon控件notifyIcon1，为控件的属性Icon添加一个icon图标, Text为鼠标在图标上时显示的tip。

2. 在Form1_SizeChanged中设置Form的ShowInTaskbar属性

3. 在notifyIcon1_Click事件中设置Form的ShowInTaskbar和WindowState属性

4. 添加ContextMenuStrip控件ContextMenuStrip1，右键托盘图标弹出菜单，设置notifyIcon1的ContextMenuStrip属性为ContextMenuStrip1。在ContextMenuStrip1中添加item(退出)。

5. notifyIcon1在MouseClick事件中，判断右键点击 并弹出ContextMenuStrip。

代码：

    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_FormClosing(object sender, FormClosingEventArgs e)
        {
            this.WindowState = FormWindowState.Minimized;
            e.Cancel = true;
        }

        private void Form1_SizeChanged(object sender, EventArgs e)
        {
            if (this.WindowState == FormWindowState.Minimized)
            {
                this.ShowInTaskbar = false;
            }
        }

        private void notifyIcon1_Click(object sender, EventArgs e)
        {
            this.ShowInTaskbar = true;
            this.WindowState = FormWindowState.Normal;
        }

        private void 退出ToolStripMenuItem_Click(object sender, EventArgs e)
        {
            Application.Exit();
        }

        private void notifyIcon1_MouseClick(object sender, MouseEventArgs e)
        {
            if (e.Button == System.Windows.Forms.MouseButtons.Right)
            {
                this.contextMenuStrip1.Show();
            }
        }
    }