All unique values for excel filter

Hi. This article explains how to return unique values from server end for excel filter checkbox. But this approach does not work for Essential JS 2 for ASP.NET Core, or I use it incorrectly. Please give me an example to get all the unique values ​​of the Excel filter for the Grid (Essential JS 2 for ASP.NET Core).\

<ejs-grid id="Grid" allowPaging="true" allowFiltering="true" actionBegin="actionBegin" toolbar="@(new List<string>() { "Add", "Edit", "Delete", "Update", "Cancel" })">      <e-data-manager url="/home/UrlDatasource" batchUrl="/Home/BatchUpdate" adaptor="UrlAdaptor"></e-data-manager>      <e-grid-filterSettings type="Excel"></e-grid-filterSettings>      ...  </ejs-grid>      <script>      function actionBegin(args) {          if (args.requestType === "filterchoicerequest") {              var filterfields = [];              var objFilter = Object.keys(args.filterModel.existingPredicate);              for (var i = 0; i < objFilter.length; i++) {                  filterfields.push(objFilter[i]);              }              filterfields.push(args.filterModel.options.field);              args.query.distincts = [];              args.query.select(filterfields); // Created the select query           }       }  </script>

public IActionResult UrlDatasource([FromBody]DataManagerRequest dm)          {              IEnumerable DataSource = order;              DataOperations operation = new DataOperations();              if (dm.Search != null && dm.Search.Count > 0)              {                  DataSource = operation.PerformSearching(DataSource, dm.Search);  //Search              }              if (dm.Sorted != null && dm.Sorted.Count > 0) //Sorting              {                  DataSource = operation.PerformSorting(DataSource, dm.Sorted);              }              if (dm.Where != null && dm.Where.Count > 0) //Filtering              {                  DataSource = operation.PerformFiltering(DataSource, dm.Where, dm.Where[0].Operator);              }              int count = DataSource.Cast<Orders>().Count();              if (dm.Select != null)              {                  DataSource = operation.PerformSelect(DataSource, dm.Select);  // Selected the columns value based on the filter request                  DataSource = DataSource.Cast<dynamic>().Distinct().AsEnumerable(); // Get the distinct values from the selected column              }              if (dm.Skip != 0)              {                  DataSource = operation.PerformSkip(DataSource, dm.Skip);   //Paging              }              if (dm.Take != 0)              {                  DataSource = operation.PerformTake(DataSource, dm.Take);              }              return dm.RequiresCounts ? Json(new { result = DataSource, count = count }) : Json(DataSource);          }

Thanks, this code works. But in my application, data is stored in SQL Server. Suppose, conditionally, that this is the Order table. I use OrderViewModel to display the data in the Grid. In my case, the tool "SQL Server Extended events" shows that with each filtering (Excel mode) there are 3 queries to the database. The first query loads 100% of the records from the table. In the second query, the filter values ​​for the column are loaded. In the third query, the filtered data is loaded. The presence of the first query does not seem acceptable in terms of performance. Perhaps I have incorrectly formed the function "public IActionResult UrlDatasource ([FromBody] DataManagerRequest dm)" for the case of using DB and ViewModel. What is the recommended way of writing code for the function "public IActionResult UrlDatasource ([FromBody] DataManagerRequest dm)" in order to minimize the amount of data transferred from SQL Server for the case of using DataOperations class with tables in DB and ViewModels?

<script>      function actionBegin(args){         if (args.requestType == "filterchoicerequest") {              // you can set filter choice count based on your needs , by default count 1000              args.filterchoicecount = 1500;          }      }  </script>

Hi. I am surprised to receive such an answer from Syncfudiom support service.Formal perfunctory replies are not needed by anyone. I again ask to answer my question on the merits. I would suggest that the employee who answers will read the discussion thread (it's not that big) from the very beginning and take into account that we are talking about ASP.NET Core - EJ 2, Grid, Excel filter, SQL Server, UrlAdaptor, DataOperations, ViewModels and and see the crux of the matter: recommended way of writing code for the function "public IActionResult UrlDatasource ([FromBody] DataManagerRequest dm)" in order to minimize the amount of data transferred from SQL Server for the case of using DataOperations class with tables in DB and ViewModels. Also, it would be nice to attach an example application.

...    namespace EJ2Grid.Controllers  {      public class HomeController : Controller      {          public static List<Orders> order = new List<Orders>();            ...         public IActionResult UrlDatasource([FromBody]DataManagerRequest dm)          {              IEnumerable DataSource = MappingFunction (order);              DataOperations operation = new DataOperations();              if (dm.Search != null && dm.Search.Count > 0)              {                  DataSource = operation.PerformSearching(DataSource, dm.Search);  //Search              }              ...             return dm.RequiresCounts ? Json(new { result = DataSource, count = count }) : Json(DataSource);          }          private List<OrderViewModel> MappingFunction (List<Orders> lstOrders)          {              List<OrderViewModel> lstOrderViewModel = new List<OrderViewModel>();              lstOrderViewModel.AddRange(lstOrders.Select(x => new OrderViewModel { OrderID = x.OrderID, CustomerID = x.CustomerID }));              return lstOrderViewModel;          }            ...           public class Orders                         //class with all columns properties          {              ...              public int OrderID { get; set; }              public int EmployeeID { get; set; }              public string CustomerID { get; set; }              public string ShipCity { get; set; }              public string ShipName { get; set; }         }            public class OrderViewModel                 //class for only displaying columns property in the grid          {              public int OrderID { get; set; }              public string CustomerID { get; set; }          }      }  }

Attachment: EJ2GridSampleM1879927353DB_d7d1535d.zip

Thavasianand S.