function api_add_values(param_SetIDs, param_SetValue) {

    //--------< api_add_values(xx) >--------

    //*convert to json items

    var setItems= JSON.stringify({

        setids: param_SetIDs, //setIDs,    //1,2,3

        setvalue: param_SetValue  //setValue //"2021-10-06

    });

    //--< send_to_api >--

    $.ajax({

        //< setup_send >

        url: '/api/apiDemo/Add_Date_To_Products/',

        contentType: "application/json",

        type: 'POST',

        data: setItems,

        //</ setup_send >

        success: function (data) {

            //--< success >--

            alert(data);

            //--</ success >--

        },

        error: function (request, message, error) {

            //--< error >--

            //handleException(request, message, error);

            alert(error);

            //--</ error >--

        }

    });

    //--</ send_to_api >--

    //--------</ api_add_values(xx) >--------

}

function onClickButtonSet(xx) {

    //--------< onClickButtonSet(xx) >--------

    //< get Date >

    var ctlSetDate = $("#ctlSetDate").dxDateBox("instance");

    var valDateSet = ctlSetDate.option('value'); 

    //</ get Date >

    //< check >

    if (valDateSet == null) { alert("no date is entered"); return; }

    var dtISOSet = valDateSet.toISOString().split("T")[0];

    //</ check >

    //< get Grid >

    var dataGrid = $("#gridDataTable").dxDataGrid("instance");

    var selectedRowsData = dataGrid.getSelectedRowsData();

    //</ get Grid >

    //*check if selected

    if (selectedRowsData.length==0) { alert("no row is selected"); return; }

    //*get selected IDs

    var selectedIDs = "";

    //--< @Loop: selectedRows >--

    for (var iRow = 0; iRow < selectedRowsData.length; iRow++) {

        var IDProduct = selectedRowsData[iRow]["IDProduct"];

        selectedIDs = selectedIDs + ";" + IDProduct;

        //console.log(selectedRowsData[iRow]);

    }

    //--</ @Loop: selectedRows >--

    if (selectedIDs.length > 0) selectedIDs = selectedIDs.substring(1);

    //< call Api >

    api_add_values(selectedIDs, dtISOSet);

    //</ call Api >

    //--------</ onClickButtonSet(xx) >--------

}

        //*Upload Data

        public class Upload_Item

        {

            public string setids { get; set; }

            public string setvalue { get; set; }

        }

        [HttpPost("Add_Date_To_Products")]

        public ActionResult Add_Date_To_Products([FromBody] Upload_Item setItems)

        {

            //-------------< UpdateGridCell() >-------------

            string sResult = JsonConvert.SerializeObject(setItems);

            return Ok(sResult);

            //-------------</ UpdateGridCell() >-------------

        }

using Microsoft.AspNetCore.Http;

using Microsoft.AspNetCore.Mvc;

using System;

using System.Collections.Generic;

using System.Linq;

using System.Threading.Tasks;

using MyApp.Models;

using DevExtreme.AspNet.Data;

using DevExtreme.AspNet.Mvc;

using MyApp.Models.DBContext;

using MvcContrib.UI.DataList;

using System.Data;

using Newtonsoft.Json;

using Microsoft.EntityFrameworkCore;

namespace MyApp.Controllers.Api

{

    [Route("api/[controller]")]

    [ApiController]

    public class apiDemoController : ControllerBase

    {

        #region Controller Init

        private readonly ApplicationDbContext _dbContext;

        public apiDemoController(ApplicationDbContext dbContext)

        {

            //----< Init: Controller >----

            _dbContext = dbContext;

            //----</ Init: Controller >----

        }

        #endregion

        [HttpGet("getGridData")]

        public object getGridData(DataSourceLoadOptions loadOptions,  string filterGridParameters)

        {

            //-------------< getDataGrid() >-------------

            var dsProducts = from tblProducts in _dbContext.tbl_Products

                                orderby tblProducts.Product ascending

                                select tblProducts;

            var dsProductDates = from tblProductDates in _dbContext.tbl_ProductDates

                orderby tblProductDates.IDProduct, tblProductDates.Date_Product ascending

                select tblProductDates;

            //--< Get Linq.Query >--

            DataTable tblMonth = new DataTable();   

            //< define Columns >

            tblMonth.Columns.Add("IDProduct", typeof(int));

            tblMonth.Columns.Add("Product", typeof(String));

            DateTime dtFrom = DateTime.Today.AddDays(- DateTime.Today.Day +1 );

            DateTime dtTo= DateTime.Today.AddMonths(6);

            DateTime dtLoop = dtFrom;

            while (dtLoop <= dtTo)

            {

                tblMonth.Columns.Add(dtLoop.ToString("yyyy-MM-01"), typeof(String));

                dtLoop = dtLoop.AddMonths(1);

            }

            //</ define Columns >

            //----< @Loop:Products >----

            foreach (var Product in dsProducts)

            {

                //----< [ Product ]----

                DataRow row = tblMonth.Rows.Add();

                row["IDProduct"] = Product.IDProduct;

                row["Product"] = Product.Product;

                //*SubQuery: Current Dates of Row Product

                var qDatesByProduct = dsProductDates.Where(p => p.IDProduct == Product.IDProduct && p.Date_Product>= dtFrom && p.Date_Product<=dtTo)

                    .Select(d=>new { dtMonth=d.Date_Product}) ;

                //----< @Loop:Products >----

                foreach (var ProductDate in qDatesByProduct)

                {

                    //----< [ Product ]----

                    string sMonth01 = ProductDate.dtMonth.ToString("yyyy-MM-01");

                    if (row[sMonth01] is System.DBNull) {

                        row[sMonth01] = ProductDate.dtMonth.ToString("yyyy-MM-dd");

                    }

                    else

                    {

                        row[sMonth01] = row[sMonth01] + ", " + ProductDate.dtMonth.ToString("yyyy-MM-dd");

                    }

                    //----</ [ Product ]----

                }

                //----</ @Loop:Products >----

                //----</ [ Product ]----

            }

                //----</ @Loop:Products >----

            List<DataRow> dataList = tblMonth.Select().ToList();

            //----< fill Data_to_View >----

            //---< @Loop: Rows >---

            //----</ fill Data_to_View >----

            return  JsonConvert.SerializeObject(tblMonth) ;

            //-------------</ getDataGrid() >-------------

        }

        [HttpPut("UpdateGridCell")]

        public ActionResult UpdateGridCell([FromForm] Dictionary<string,string> cell)

        {

            //-------------< UpdateGridCell() >-------------

            var sKey = cell["key"]; //ID=A

            var sCell_Column_Value = cell["values"]; //{"..":".."}

            sCell_Column_Value = sCell_Column_Value.Substring(1,sCell_Column_Value.Length-2);  //"..":".."

            string[] arrCell_Column_Value = sCell_Column_Value.Split(':');

            string sColumn_Name = arrCell_Column_Value[0];       //"col: 2021-10-01"

            string sCell_Value = arrCell_Column_Value[1];        //"val: 2021-10-10;2021-10-20;"

            sCell_Value = sCell_Value.Replace("\"","");

            DateTime dtCell = DateTime.Parse(sCell_Value);

            int IDProduct = Convert.ToInt32(sKey);

            ProductDateModel productDate = _dbContext.tbl_ProductDates.SingleOrDefault(p => p.IDProduct == IDProduct && p.Date_Product==dtCell);

            if(productDate == null)

            {

                try

                {

                    //< new ProductDate >

                    ProductDateModel newProductDate = new ProductDateModel();

                    newProductDate.Date_Product = dtCell;

                    newProductDate.IDProduct = IDProduct;

                    _dbContext.tbl_ProductDates.Add(newProductDate);    //*add 1 record

                    //</ new ProductDate >

                    _dbContext.SaveChanges();       //*update all in table

                    //----< Save Data >----           

                    try

                    {

                        //_dbContext.Update(newProductDate);

                        _dbContext.SaveChanges();

                    }

                    catch (DbUpdateConcurrencyException)

                    {

                        return Content("Update Error");

                    }

                    //----</ Save Data >----

                    //else

                    //{

                    //    //< Add on Server >

                    //    _dbContext.tbl_Notes.Add(note);

                    //    _dbContext.SaveChanges();

                    //    IDNote = note.IDNote;

                    //    //</ Add on Server >

                    //}

                    //await _dbContext.SaveChangesAsync(true);

                }

                catch (DbUpdateConcurrencyException ex)

                {

                    return Content("Error in saving ID:" + IDProduct + " Date:" +  productDate.Date_Product + ".. " + ex.Message);

                }

            }

            return Ok();

            //-------------</ UpdateGridCell() >-------------

        }

        //*Upload Data

        public class Upload_Item

        {

            public string setids { get; set; }

            public string setvalue { get; set; }

        }

        [HttpPost("Add_Date_To_Products")]

        public ActionResult Add_Date_To_Products([FromBody] Upload_Item setItems)

        {

            //-------------< UpdateGridCell() >-------------

            string sResult = JsonConvert.SerializeObject(setItems);

            return Ok(sResult);

            //-------------</ UpdateGridCell() >-------------

        }

    }

}