namespace TestWcf
{
    [ServiceContract]
    public interface ITestServiceWcf
    {
       [OperationContract]
        Customer getCustomer(string login, string password);
       
    }

    [DataContract]
    public class Customer
    {               
        public Customer(int no, string name)
        {
            No = no;
            Name = name;
        }
        [DataMember]
        public int No { get; private set; }

        [DataMember]
        public string Name { get; private set; }

        [DataMember]
        public string Address { get;  set; }
        
        [OperationContract]
        public string getIds()
        {
            if (this.No == 1)
                return "AAAA";
            else
                return "BBBB";
        }            
   }
}


namespace TestWcf
{  
    public class TestServiceWcf : ITestServiceWcf
    {       

        public Customer getCustomer(string login, string password)
        {
            Customer cust = new Customer (1,"Test");
            
            return cust;
        }             
    }
}

<?xml version="1.0" encoding="utf-8" ?>
<configuration>

  <appSettings>
    <add key="aspnet:UseTaskFriendlySynchronizationContext" value="true" />
  </appSettings>
  <system.web>
    <compilation debug="true" />
  </system.web>  
  <system.serviceModel>
    <services>
      <service name="TestWcf.TestServiceWcf">
        <host>
          <baseAddresses>
            <add baseAddress = "http://localhost:8733/Design_Time_Addresses/TestWcf/Service1/" />
          </baseAddresses>
        </host>        
        <endpoint address="" binding="basicHttpBinding" contract="TestWcf.ITestServiceWcf">
          <identity>
            <dns value="localhost"/>
          </identity>
        </endpoint>        
        <endpoint address="mex" binding="mexHttpBinding" contract="IMetadataExchange"/>
      </service>    
    </services>
    <behaviors>
      <serviceBehaviors>
        <behavior>          
          <serviceMetadata httpGetEnabled="True" httpsGetEnabled="True"/>          
          <serviceDebug includeExceptionDetailInFaults="False" />
        </behavior>
      </serviceBehaviors>
    </behaviors>
  </system.serviceModel>

</configuration>