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();
}
}
}