WINFORM 中mdi结构的子窗体不重复创建

            foreach (Form childrenForm in this.MdiChildren)

            {

                //检测是不是当前子窗体名称

                if (childrenForm is 窗体名称)

                {

                    //是的话就是把他显示

                    childrenForm.Visible = true;

                    //并激活该窗体

                    childrenForm.Activate();

                    return;

                }

            }//没有就把窗体显示出来，如下代码

            FormPZXX frmPZXX = new FormPZXX();

            frmPZXX.MdiParent = this;

            frmPZXX.Show();