menuStrip鼠标滑过自动弹出

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

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

        private void FrmMain_Load(object sender, EventArgs e)
        {
            for (int i = 0; i < this.menuStrip1.Items.Count ; i++)
            {
                this.menuStrip1.Items[i].MouseHover += new EventHandler(FrmMain_MouseHover);
            }
            /*
            this.menuStrip1.Items[0].MouseHover += new EventHandler(FrmMain_MouseHover);
            this.menuStrip1.Items[1].MouseHover += new EventHandler(FrmMain_MouseHover);
            this.menuStrip1.Items[2].MouseHover += new EventHandler(FrmMain_MouseHover);
            this.menuStrip1.Items[3].MouseHover += new EventHandler(FrmMain_MouseHover);
            this.menuStrip1.Items[4].MouseHover += new EventHandler(FrmMain_MouseHover);
            */

        }

        void FrmMain_MouseHover(object sender, EventArgs e)
        {
            if (sender is ToolStripDropDownItem)
            {
                ToolStripDropDownItem item = sender as ToolStripDropDownItem;
                if (item.HasDropDownItems && !item.DropDown.Visible)
                {
                    item.ShowDropDown();
                }
            }

        }
    }