namespace DatabaseTransferViaWcf
{
    [ServiceContract]
    public interface IService1
    {
        [OperationContract]
        int generateId();
    }
}

namespace DatabaseTransferViaWcf
{
     public class Service1 : IService1
     {
         public int generateId()
         {
             return 5700 ;
         }
    }
}

public partial class Transfer : Window
{
    private void button9_Click(object sender, RoutedEventArgs e)
    {
        ServiceHost host = null;
        try
        {
            using (ServiceHost host = new ServiceHost(typeof(SendRecieveData.Service1)))
            {
                host.Open();
                Console.WriteLine("The service is ready.");
                Console.WriteLine("Press <enter /> to terminate service.");
                Console.ReadLine();
            }
            wcfHostId = wcf.generateId();
            textBox5.Text = "" + wcfHostId;
        }
        catch (Exception ex)
        {

            MessageBox.Show("Error = " + ex.Message);
        }

    }
}