C# Winform 防止子窗体重复打开



            bool v = false;
            foreach (Form frm in this.MdiChildren)  //防止子窗体重复打开
            {
                if (frm.Name == "frm1CounterTower")  //frm1CounterTower 为子窗体的名称
                {
                    v = true;
                }
            }
            if (!v)
            {
                frm1CounterTower myfrm = new frm1CounterTower();
                myfrm.TopLevel = false;
                myfrm.MdiParent = this;
                myfrm.StartPosition = FormStartPosition.CenterScreen;
                myfrm.Show();
            }