Question

Do you need to create the same object in iOS that is taken by the POST method on the WCF service?

Example of the POST call in WCF service

[OperationContract]
    [WebInvoke(Method = "POST",
       ResponseFormat = WebMessageFormat.Json,
       RequestFormat = WebMessageFormat.Json,
       BodyStyle = WebMessageBodyStyle.Wrapped,
       UriTemplate = "")]
       //method
       Employee PostEmp(Employee emp);
[DataContract]
public class Employee
{
    [DataMember]
    public string firstname { get; set; }
    [DataMember]
    public string idkey { get; set; }
    [DataMember]
    public string lastname { get; set; }
    [DataMember]
    public string salary { get; set; }

    public Employee(string first, string id, string sal, string last)
    {
        firstname = first;
        idkey = id;
        salary = sal;
        lastname = last;

    }

Answer 1

No, you do not create those POCO classes on iOS. iOS will just read the Json string response from the WCF service. The iOS device will also post Json to the service url.

The wcf service will do all serialization/deserialization for you.