[System.Web.Http.RoutePrefix("api/PurchaseOrder")]
public class PurchaseOrderController : ApiController
{
    private static ILog logger = log4net.LogManager.GetLogger(System.Reflection.MethodBase.GetCurrentMethod().DeclaringType);

    [System.Web.Http.Route("PagingCriticalPart")]
    [System.Web.Http.HttpPost]
    public JsonResult PagingCriticalPart([FromBody] Helper.DataTablesBase model)
    {
        logger.Info("PagingCriticalPart");
        JsonResult jsonResult = new JsonResult();
        try
        {
            if (model == null) { logger.Info("model is null."); }

            int filteredResultsCount;
            int totalResultsCount;
            var res = BLL.PurchaseOrderHandler.PagingCriticalPart(model, out filteredResultsCount, out totalResultsCount);

            var result = new List<Models.T_CT2_CriticalPart>(res.Count);
            foreach (var s in res)
            {
                // simple remapping adding extra info to found dataset
                result.Add(new Models.T_CT2_CriticalPart
                {
                    active = s.active,
                    createBy = s.createBy,
                    createdDate = s.createdDate,
                    id = s.id,
                    modifiedBy = s.modifiedBy,
                    modifiedDate = s.modifiedDate,
                    partDescription = s.partDescription,
                    partNumber = s.partNumber
                });
            };

            jsonResult.Data = new
            {
                draw = model.draw,
                recordsTotal = totalResultsCount,
                recordsFiltered = filteredResultsCount,
                data = result
            };
            return jsonResult;
        }
        catch (Exception exception)
        {
            logger.Error("PagingCriticalPart", exception);
            string exceptionMessage = ((string.IsNullOrEmpty(exception.Message)) ? "" : Environment.NewLine + Environment.NewLine + exception.Message);
            string innerExceptionMessage = ((exception.InnerException == null) ? "" : ((string.IsNullOrEmpty(exception.InnerException.Message)) ? "" : Environment.NewLine + Environment.NewLine + exception.InnerException.Message));
            jsonResult.Data = new
            {
                draw = model.draw,
                recordsTotal = 0,
                recordsFiltered = 0,
                data = new { },
                error = exception.Message
            };
            return jsonResult;
        }
    }

    [System.Web.Http.Route("UploadRawMaterialData")]
    [System.Web.Http.HttpPost]
    public JsonResult UploadRawMaterialData(string rawMaterialSupplierData)
    {
        JsonResult jsonResult = new JsonResult();
        jsonResult.Data = new
        {
            uploadSuccess = true
        };
        return jsonResult;
    }
}

"ajax": {
    url: 'http://localhost/ControlTower2WebAPI/api/PurchaseOrder/PagingCriticalPart',
    type: 'POST',
    contentType: "application/json",
    data: function (data) {
        //debugger;
        var model = {
            draw: data.draw,
            start: data.start,
            length: data.length,
            columns: data.columns,
            search: data.search,
            order: data.order
        };
        return JSON.stringify(model);
    },
    failure: function (result) {
        debugger;
        alert("Error occurred while trying to get data from server: " + result.sEcho);
    },
    error: function (XMLHttpRequest, textStatus, errorThrown) {
        debugger;
        alert("Error occurred while trying to get data from server!");
    },
    dataSrc: function (json) {
        //debugger;
        for (key in json.Data) { json[key] = json.Data[key]; }
        delete json['Data'];
        return json.data;
    }
}

var data = Newtonsoft.Json.JsonConvert.SerializeObject(rawMaterialVendorUploads);
string apiURL = @"http://localhost/ControlTower2WebAPI/api/PurchaseOrder/UploadRawMaterialData";
HttpWebRequest request = (HttpWebRequest)WebRequest.Create(apiURL);
request.UseDefaultCredentials = true;
request.Method = "POST";
request.ContentType = "application/json";
request.ContentLength = data.Length;
using (Stream webStream = request.GetRequestStream())
using (StreamWriter requestWriter = new StreamWriter(webStream, System.Text.Encoding.ASCII))
{
    requestWriter.Write(data);
}

try
{
    WebResponse webResponse = request.GetResponse();
    using (Stream webStream = webResponse.GetResponseStream() ?? Stream.Null)
    using (StreamReader responseReader = new StreamReader(webStream))
    {
        string response = responseReader.ReadToEnd();
    }
}
catch (Exception exception)
{

}

{
    "Message": "No HTTP resource was found that matches the request URI 'http://localhost/ControlTower2WebAPI/api/PurchaseOrder/UploadRawMaterialData'.",
    "MessageDetail": "No action was found on the controller 'PurchaseOrder' that matches the request."
}

http://localhost/ControlTower2WebAPI/api/PurchaseOrder/UploadRawMaterialData?rawMaterialSupplierData=test