private void btnAddStudent_Click_1(object sender, EventArgs e)
        {
            frmRegisterStudent frmRegisterStudent = frmRegisterStudent.GetInstance();

            frmRegisterStudent.Show();
            this.Hide();
        }
 public static frmRegisterStudent GetInstance()
 {
     if (Instance == null)
     {
         frmRegisterStudent new_Instance = new frmRegisterStudent();
         return(new_Instance);
     }
     return(Instance);
 }