Passing generics between DAL and WCF

Question

Hi,
I have a solution with layers including wcf. UI calls the WCF.
I am getting an error when calling a List in Service1.svc from the DAL layer. How can I fix it?
Thanks
var client = new ServiceReference1.PizzaAPIClient();
var customer = new ServiceReference1.CustomerAPI();
customer.PhoneNumber = txtPhone.text;
List<ServiceReference1.CustomerAPI> lstcustomers = client.GetCustomerByPhoneNumber(customer);
WCF
IService1.cs
using BL;
namespace WcfService1
[ServiceContract]
public interface IPizzaAPI
// TODO: Add your service operations here
[OperationContract]
List<CustomerAPI> GetCustomerByPhoneNumber(CustomerAPI customer);
[DataContract]
public class OrderAPI
[DataMember]
public string OrderName { get; set; }
[DataContract]
public class CustomerAPI
int _Customerid;
string _firstName;
string _lastName;
string _phonenumber;
public CustomerAPI (int custId, string firstname, string lastName, string phonenumber)
_Customerid = custId;
_lastName = lastName;
_firstName = firstname;
_phonenumber = phonenumber;
[DataMember]
public string PhoneNumber
get { return _phonenumber; }
set { _phonenumber = value; }
[DataMember]
public int CustomerId
get { return _Customerid; }
set { _Customerid = value; }
--omitted for brevity
Service1.svc
using DL;
using BL;
namespace WcfService1
// NOTE: You can use the "Rename" command on the "Refactor" menu to change the class name "Service1" in code, svc and config file together.
public class Service1 : IPizzaAPI
List<CustomerAPI> customerLst = new List<CustomerAPI>();
// Method returning the details of the student for the studentId
public List<CustomerAPI> GetCustomerByPhoneNumber(CustomerAPI customer)
List<CustomerAPI> customerLst = DL.CustomerDB.GetCustomerByPhoneNumber(customer.PhoneNumber); //Error 8 Cannot implicitly convert type 'System.Collections.Generic.List<BL.CustomerBL>' to 'System.Collections.Generic.List<WcfService1.CustomerAPI>'
return customerLst;
CustomerBL.cs -Business Logic Layer
namespace BL
public class CustomerBL
private string phonenumber;
public int CustomerId { get; set; }
public string FirstName { get; set; }
public string LastName { get; set; }
public String PhoneNumber
get
return this.phonenumber;
set
this.phonenumber = value;
if (this.PhoneNumber == "")
throw new Exception("Please provide Tel ...");
CustomerDB.cs -DAL layer
using BL;
namespace DL
public static class CustomerDB
public static SqlConnection InitConnection()
DL.ConStrings connstrings = new DL.ConStrings();
return connstrings.GetPizzaDeliveryConnection();
//public static CustomerBL[] GetCustomerByPhoneNumber(string phonenumber)
public static List<CustomerBL> GetCustomerByPhoneNumber(string phonenumber)
SqlConnection connstrings = InitConnection();
using (var connection = connstrings)//using doesn't require connection closed
var cmd = connection.CreateCommand();
cmd.CommandText = "GetCustomerByPhoneNumber";
cmd.CommandType = System.Data.CommandType.StoredProcedure;
cmd.Parameters.AddWithValue("@phonenumber", phonenumber);
connection.Open();
var customers = new List<CustomerBL>();
var reader = cmd.ExecuteReader();
while (reader.Read())
var customer = new CustomerBL();
customer.CustomerId = Convert.ToInt32(reader["CustomerId"]);
customer.FirstName = Convert.ToString(reader["FirstName"]);
customer.LastName = Convert.ToString(reader["LastName"]);
customer.Address = Convert.ToString(reader["Address"]);
customers.Add(customer);
return customers;

Answer 1

Hi collie12,
>>Cannot implicitly convert type 'System.Collections.Generic.List<BL.CustomerBL>' to 'System.Collections.Generic.List<WcfService1.CustomerAPI>'   
As the error said that we can not simply convert the 'System.Collections.Generic.List<BL.CustomerBL>' to 'System.Collections.Generic.List<WcfService1.CustomerAPI>' by using the following code, because they are different classes:
List<CustomerAPI> customerLst = DL.CustomerDB.GetCustomerByPhoneNumber(customer.PhoneNumber);
Please try to modify the above code as following:
public List<CustomerAPI> GetCustomerByPhoneNumber(CustomerAPI customer)
List<BL.CustomerBL> CustomerBLList= DL.CustomerDB.GetCustomerByPhoneNumber(customer.PhoneNumber);
List<CustomerAPI> CustomerAPIList = new List<CustomerAPI>();
foreach (var CustomerBL in CustomerBLList)
CustomerAPI CustomerAPI = new CustomerAPI(CustomerBL.CustomerId, CustomerBL.FirstName, CustomerBL.LastName, CustomerBL.PhoneNumber);
CustomerAPIList.Add(CustomerAPI);
return CustomerAPIList;
Best Regards,
Amy Peng
We are trying to better understand customer views on social support experience, so your participation in this interview project would be greatly appreciated if you have time. Thanks for helping make community forums a great place.
Click
HERE to participate the survey.