DTO:
 [DataContract]
    public class CampaignSignUpDTO
    {
        [DataMember]
        public int pageId { get; set; }
        [DataMember]
//eto tova e ot radio butona
        public string checkedValue { get; set; }
        [DataMember]
        public string name { get; set; }
        [DataMember]
        public string adress { get; set; }
        [DataMember]
        public string city { get; set; }
        [DataMember]
        public string country { get; set; }
        [DataMember]
        public string phone { get; set; }
        [DataMember]
        public string email { get; set; }
        [DataMember]
        public bool newsletter { get; set; }
        [DataMember]
        public bool partnerNewsletter { get; set; }
    }


----------.js file-a-------------

  $.ajax({
                type: "POST",
                url: '/api/campaignsignups/register?lang=lang',
                dataType: "JSON",
                data: {

                    PageId: $.trim($('.beoplay-form .beoplay-pageId input').val()),
                    Name: $.trim($('.beoplay-form .beoplay-name input').val()),
                    Address: $.trim($('.beoplay-form .beoplay-address input').val()),
                    City: $('.beoplay-form .beoplay-city input').val(),
                    Country: $.trim($('.beoplay-form .beoplay-country input').val()),
                    Phone: $.trim($('.beoplay-form .beoplay-phone input').val()),
                    Email: $.trim($('.beoplay-form .beoplay-email input').val()),

                    Language: $('.beoplay-form').attr('data-language')
                },