private void UpdatePointOfContact(PointOfContact poc)
        {
            try
            {
                ServiceContactHelper client = new ServiceContactHelper();

                if (event_ != null)
                {
                    client.EditPointOfContact(user, event_.EventID, poc.PointOfContactID, txtContactName.Text, txtContactPosition.Text, txtContactTel.Text, txtContactEmail.Text);
                }
                else
                {
                    client.EditPointOfContact(user, -1, poc.PointOfContactID, txtContactName.Text, txtContactPosition.Text, txtContactTel.Text, txtContactEmail.Text);
                }
                client.Close();
                MessageBox.Show("Operation Success");
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }
        }