c# – 右键菜单和菜单行

问题：
有两个问题：
*当我点击右键时,菜单的左角并不完全位于箭头的位置.
*如何在菜单中创建一行？

关于菜单的主要问题

需要支持来创建这两个redmark.

private void lstV_Stock_MouseUp(object sender,MouseEventArgs e)
{
    switch (e.Button)
    {

        // Right mouse click
            case MouseButtons.Right:


                ContextMenu myContextMenu = new ContextMenu();

                MenuItem menuItem1 = new MenuItem("New product");
                MenuItem menuItem2 = new MenuItem("Delete");
                MenuItem menuItem3 = new MenuItem("Add quantity");


                // Clear all previously added MenuItems.
                myContextMenu.MenuItems.Clear();

                myContextMenu.MenuItems.Add(menuItem1);
                myContextMenu.MenuItems.Add(menuItem2);
                myContextMenu.MenuItems.Add(menuItem3);

                if (lstV_Stock.SelectedItems.Count > 0) 
                {

                    foreach (ListViewItem item in lstV_Stock.SelectedItems)
                    {
                        myContextMenu.MenuItems[1].Visible = true;
                        myContextMenu.MenuItems[2].Visible = true;
                        myContextMenu.MenuItems[0].Visible = false;
                    }

                }
                else
                {
                    myContextMenu.MenuItems[1].Visible = false;
                    myContextMenu.MenuItems[2].Visible = false;
                    myContextMenu.MenuItems[0].Visible = true;
                }

                myContextMenu.Show(lstV_Stock,this.PointToClient(Cursor.Position),LeftRightAlignment.Right);



                menuItem1.Click += new System.EventHandler(this.menuItem1_Click);


                break;

        }