menuStrip鼠标经过自动显示菜单

//---------------------------------------------------------------------------------
private void Form1_Load(object sender, EventArgs e)
{
    this.menuStrip1.Items[].MouseHover += new EventHandler(Form1_MouseHover);
}

//---------------------------------------------------------------------------------
void Form1_MouseHover(object sender, EventArgs e)
{
    if (sender is ToolStripDropDownItem)
    {
        ToolStripDropDownItem item = sender as ToolStripDropDownItem;
        if (item.HasDropDownItems && !item.DropDown.Visible)
        {
            item.ShowDropDown();
        }
    }
}