几种MDI窗体‘单例’显示代码

几种

public void CreatChildForm(string frm_ChildName)
  {
   string frm_Name="GainerMain."+frm_ChildName.Trim();
   foreach(Form frm_Temp in this.MdiChildren)
    if(frm_Temp.GetType().ToString() == frm_Name.Trim())
    {
     if(frm_Temp.WindowState == FormWindowState.Minimized)
     frm_Temp.WindowState = FormWindowState.Normal;
     frm_Temp.Focus();
     return;
    }
   
   Form frm_Child =(Form)Activator.CreateInstance(Type.GetType(frm_Name));
   frm_Child.MdiParent = this;
   frm_Child.Show();   
  }

  private void CreatChildForm(string frm_ChildName,string strType)
  {
   string frm_Name="GainerMain."+frm_ChildName.Trim();
   foreach(Form frm_Temp in this.MdiChildren)
    if(frm_Temp.GetType().ToString() == frm_Name.Trim())
    {
     if(frm_Temp.WindowState == FormWindowState.Minimized)
      frm_Temp.WindowState = FormWindowState.Normal;
     frm_Temp.Focus();
     return;
    }
   
   Form frm_Child =(Form)Activator.CreateInstance(Type.GetType(frm_Name));
   frm_Child.MdiParent = this;
   frm_Child.Show();
   frm_Child.Dock =System.Windows.Forms.DockStyle.Fill;//平铺，最大化
  }

 private void ShowChildMDIEx(string strFrmModleName , string strTitle)
        {
            string strAssembly = "Dhthx.TicketOffice.dll";
            string frmName = strFrmModleName;
            foreach (Form frmTemp in this.MdiChildren)
                if (frmTemp.GetType().ToString() == frmName.Trim())
                {
                    if (frmTemp.WindowState == FormWindowState.Minimized)
                        frmTemp.WindowState = FormWindowState.Normal;
                    frmTemp.Close();
                }

            Assembly assembly = Assembly.LoadFrom(Application.StartupPath + "\\" + strAssembly);
            Type type = assembly.GetType(frmName);
            Form frmChild = (Form)Activator.CreateInstance(type);
            frmChild.MdiParent = this;
            frmChild.WindowState = FormWindowState.Normal;
            frmChild.Show();
            frmChild.Dock = System.Windows.Forms.DockStyle.Fill;//平铺，最大化
  }