private void updateBTN_Click(object sender, EventArgs e)
 {
     if (r == null)
     {
         MessageBox.Show("select Librarian ");
     }
     else
     {
         bool Isopen = false;
         foreach (Form f in Application.OpenForms)
         {
             if (f.Text == "Librarian_Reg")
             {
                 Isopen = true;
                 f.BringToFront();
                 break;
             }
         }
         if (Isopen == false)
         {
             Librarian_Reg lr = new Librarian_Reg(librarian, "update");
             lr.Show();
         }
     }
 }
        private void admin_Click(object sender, EventArgs e)
        {
            Button button = sender as Button;

            if (button.Name.Equals("register_Btn"))
            {
                bool Isopen = false;
                foreach (Form f in Application.OpenForms)
                {
                    if (f.Text == "admin_Reg")
                    {
                        Isopen = true;
                        f.BringToFront();
                        break;
                    }
                }
                if (Isopen == false)
                {
                    Librarian_Reg adr = new Librarian_Reg();
                    adr.Show();
                }
            }
            if (button.Name.Equals("changePass_Btn"))
            {
                bool Isopen = false;
                foreach (Form C in Application.OpenForms)
                {
                    if (C.Text == "Change_Password")
                    {
                        Isopen = true;
                        C.BringToFront();
                        break;
                    }
                }
                if (Isopen == false)
                {
                    Change_Password cp = new Change_Password();
                    cp.Show();
                }
            }
        }