WebClient UploadString POST Object as JSON

            string apiUrl = "http://localhost:14101/Print/MutfakAdisyonYazdir";

            var req = new MutfakAdisyonYazdir_RequestDTO();
            req.TokenGuid = Guid.NewGuid().ToString();
            req.AdisyonSiparisIdler = new List<long>() { 123, 234, 345, 456 };

            string inputJson = JsonHelper.Serialize(req);
            WebClient client = new WebClient();
            client.Headers["Content-type"] = "application/json";
            client.Encoding = Encoding.UTF8;
            string json = client.UploadString(apiUrl, inputJson);

            var resp = JsonHelper.Deserialize<BaseResponseDTO>(json);