private void permitButton_Click(object sender, EventArgs e)
        {
            int status = CenterHandler.GetCenterStatus(LoginHandler.CenterId);

            if (status == 1)
            {
                if (nidTextBox.Text != "")
                {
                    try
                    {
                        long         nid = long.Parse(nidTextBox.Text);
                        DialogResult dr  = MessageBox.Show(string.Format("Are you sure to permit voter with NID {0} to vote?", nid), "Confirm?", MessageBoxButtons.YesNo, MessageBoxIcon.Question);
                        if (dr == DialogResult.Yes)
                        {
                            if (VoterHandler.Permit(nid))
                            {
                                MessageBox.Show("Voter Permitted.");
                            }
                            else
                            {
                                MessageBox.Show("Voter Not Permitted. Please check status.");
                            }
                        }
                    }
                    catch (Exception ex)
                    {
                        MessageBox.Show("Enter proper NID.");
                    }
                }
                else
                {
                    MessageBox.Show("Enter proper NID.");
                }
            }
            else if (status == 2)
            {
                MessageBox.Show("Center Blocked.");
            }
            else
            {
                MessageBox.Show("Election is not going on currently.");
            }
        }