一段比较爽 的 MDI 窗体中打开子窗体的函数。 建议大家使用

  private void OpenChild(string Frmnamespace, string ChildTypeName)
        {
            int ret = 0;
            foreach (Form frm in MdiChildren)
            {
                if (frm.GetType().Name == ChildTypeName)
                {
                    frm.Activate();
                    ret = 1;
                    break;
                }
            }
            if (0 == ret)
            {
                string className = Frmnamespace + "." + ChildTypeName;
                Form Instance = (Form) Assembly.Load(Frmnamespace).CreateInstance(className);
          
                Instance.MdiParent = this;
            

                Instance.Show();
            
            }
        }

private void LbtUserManager_ItemClick(object sender, ItemClickEventArgs e)
        {
            OpenChild("OuterRingRoad", "frmUserManager");
        }

        private void MenuUserPopdemod_ItemClick(object sender, ItemClickEventArgs e)
        {
            OpenChild("OuterRingRoad", "frmUserPopdemod");
        }

        private void MenuCurrentTimeData_ItemClick(object sender, ItemClickEventArgs e)
        {
            OpenChild("ORRTLB", "frmNowVDIInfo");
        }

        private void MenuCarCheckConfig_ItemClick(object sender, ItemClickEventArgs e)
        {
            OpenChild("ORRTLB", "frmVDISetting");
        }