how to write the code for this : public string[] GetEmployeerid()

using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.Serialization;
using System.ServiceModel;
using System.Text;
 
namespace Employee
{
    // NOTE: If you change the interface name "IService1" here, you must also update the reference to "IService1" in App.config.
    [ServiceContract]
    public interface IService1
    {
        [OperationContract]
        List<CompositeType> GetEmployee(String Employeerid);
 
        [OperationContract]
        CompositeType GetDataUsingDataContract(CompositeType composite);
 
        // TODO: Add your service operations here
    }
 
    // Use a data contract as illustrated in the sample below to add composite types to service operations
    [DataContract]
    public class CompositeType
    {
          int   empid;
         string ename;
         string address;
         string city ;
         string state ;
         string employeerid;
 
        [DataMember]
         public int Empid
        {
            get { return empid; }
            set { empid = value; }
        }
 
        [DataMember]
        public string Ename
        {
            get { return ename; }
            set { ename = value; }
        }
        [DataMember]
        public string Address
        {
            get { return address; }
            set { address = value; }
        }
        [DataMember]
        public string City
        {
            get { return city; }
            set { city = value; }
        }
        [DataMember]
        public string State
        {
            get { return state; }
            set { state = value; }
        }
        [DataMember]
        public string Employeerid
        {
            get { return employeerid; }
            set { employeerid = value; }
        }
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.Serialization;
using System.ServiceModel;
using System.Text;
 
namespace Employee
{
    // NOTE: If you change the class name "Service1" here, you must also update the reference to "Service1" in App.config.
    public class Service1 : IService1
    {
        public string[] GetEmployeerid()
        {
            String strConnection = ConfigurationManager.ConnectionStrings["MyConsString"].ConnectionString;
            SqlConnection conn = new SqlConnection(strConnection);
            SqlCommand cmd = new SqlCommand("select * from Employeertable ", conn);
            conn.Open();
             
 
            
        }
 
        public CompositeType GetDataUsingDataContract(CompositeType composite)
        {
            List<compositetype> Employee = new List<compositetype>();
            {
                String strConnection = ConfigurationManager.ConnectionStrings["MyConsString"].ConnectionString;
                SqlConnection conn = new SqlConnection(strConnection);
                SqlCommand cmd = new SqlCommand("select * from Employeetable ", conn);
                conn.Open();
                SqlDataAdapter da = new SqlDataAdapter(cmd);
                DataTable dt = new DataTable();
                da.Fill(dt);
                if (dt.Rows.Count > 0)
                {
                    for (int i = 0; i < dt.Rows.Count; i++)
                    {
                        Employee obj = new Employee();
                        obj.Empid = Convert.ToInt32(dt.Rows[i]["Empid"].ToString());
                        obj.Ename = dt.Rows[i]["Ename"].ToString();
                        obj.Address = dt.Rows[i]["Address"].ToString();
                        obj.City = dt.Rows[i]["City"].ToString();
                        obj.State = dt.Rows[i]["State"].ToString();
                        obj.Employeerid = dt.Rows[i]["Employeerid"].ToString();
                        Employee.Add(obj);
                    }
                }
                conn.Close();
            }
            return Employee;
        }
 
        }
    }