//定义一个Hostt
private ToolStripControlHost _controlHost;

private void CreateHost(Control control)
        {
            if (control == null)
            {
                throw new ArgumentException("control");
            }

            _popupControl = control;
            //将控件加入Host，通常是用户控件，也可以手动加入其它控件
            _controlHost = new ToolStripControlHost(control, "popupControlHost");
            _controlHost.AutoSize = false;
            _controlHost.Padding = Padding.Empty;
            _controlHost.Margin = Padding.Empty;
            base.Size = new Size(
                control.Size.Width + Padding.Horizontal,
                control.Size.Height + Padding.Vertical);
            //将该Host加入本类容器中。
            base.Items.Add(_controlHost);
        }

------解决方案--------------------

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