private void button3_Click(object sender, EventArgs e)
        {
            var client = new ServiceReference.EstacionamentoServiceClient();

            try
            {
                int vagasR = client.VagasRestantes();
                MessageBox.Show(String.Format("Existem {0} vagas.", vagasR));
                textBox1.Text = string.Empty;
            }
            catch (Exception)
            {
                throw;
            }
        }
        private void button2_Click(object sender, EventArgs e)
        {
            string placa  = textBox1.Text;
            var    client = new ServiceReference.EstacionamentoServiceClient();

            try
            {
                double valor = client.CheckOut(placa);
                client.Close();

                MessageBox.Show(String.Format("Placa '{0}' valor de R${1}.", placa, valor));
                textBox1.Text = string.Empty;
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }
        }
        private void button1_Click(object sender, EventArgs e)
        {
            string placa  = textBox1.Text;
            var    client = new ServiceReference.EstacionamentoServiceClient();

            try
            {
                client.Checkin(placa);
                client.Close();

                MessageBox.Show(String.Format("Placa '{0}' adicionada.", placa));
                textBox1.Text = string.Empty;
            }
            catch (Exception ex)
            {
                client.Abort();
                MessageBox.Show(ex.Message);
            }
        }