Aggregate all page

[Kulcsár Norbert]

Hi Team!

It is possible to aggregate a column from the whole datasource, not just the current page? I have a custom aggregate function, but I can only get the current page data from the data attribute.

Thank you!

[Praveenkumar Gajendiran]

Hi Kulcsár,  

Greetings from Syncfusion support. 

Query : It is possible to aggregate a column from the whole datasource, not just the current page? I have a custom aggregate function, but I can only get the current page data from the data attribute..  

 

Before proceeding your query we would like to share some behavior of EJ2 Grid Aggregates. 

By default in EJ2 Grid, the Aggregates are calculated for entire Grid data when the grid contains local dataSource. If the Grid having remote data then you need to calculate aggregates at server side and return the aggregate value to grid as like following code example. 

The below code is used for Url adaptor. 

  public IActionResult UrlDatasource([FromBody]DataManagerRequest dm) 

        { 

            IEnumerable DataSource = OrdersDetails.GetAllRecords(); 

            DataOperations operation = new DataOperations(); 

            . . . .  

            List<string> str = new List<string>(); 

            if (dm.Aggregates != null) 

            { 

                for (var i = 0; i < dm.Aggregates.Count; i++) 

                    str.Add(dm.Aggregates[i].Field); 

            } 

            IEnumerable aggregate = operation.PerformSelect(DataSource, str); 

            int count = DataSource.Cast<OrdersDetails>().Count(); 

            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, aggregate = aggregate }) : Json(DataSource); 

        } 

When using custom aggregates in the grid, you can get only the current page records in the custom aggregate function’s arguments.  

Based on your query we understood that you need to perform calculation on entire grid dataSource in the “customAggregateFn”.  If you are using local data, you can use the following workaround to calculate aggregate value from entire data by using CustomAggregateFn (because we can get entire data from grid.dataSource).  This is demonstrated in the below code example. 

var customAggregateFn = function(data) { 

  //we can get the current page records from its args -data 

  var gridData = grid.dataSource; // get the entire grid datasource by using gridObj.dataSource  which returns entire data if the grid having local dataSource 

 var totalSum = 0; 

// do your calculation as you want with the entire dataset 

  for (var i = 0; i < gridData.length; i++) { 

    totalSum = totalSum + gridData[i]['Freight']; 

  } 

  return totalSum; // return the calculated value 

}; 

var grid = new ej.grids.Grid({ 

  dataSource: window.orderData, 

  allowPaging: true, 

  pageSettings: { pageCount: 5 }, 

  columns: [ 

    { field: 'CustomerName', headerText: 'Customer Name', width: 150 }, 

    { field: 'Freight', width: 160, format: 'C2', textAlign: 'Right' }, 

    { 

      field: 'OrderDate', 

      headerText: 'Order Date', 

      width: 130, 

      format: 'yMd', 

      textAlign: 'Right' 

    }, 

    { field: 'ShipCountry', headerText: 'Ship Country', width: 140 } 

  ], 

  aggregates: [ 

    { 

      columns: [ 

        { 

          type: 'Sum', 

          field: 'Freight', 

          format: 'C2', 

          footerTemplate: 'Sum: ${Sum}' 

        } 

      ] 

    }, 

    { 

      columns: [ 

        { 

          type: 'Custom', 

          format: 'C2', 

          customAggregate: customAggregateFn, 

          field: 'Freight', 

          footerTemplate: 'Custom: ${Custom}' 

        } 

      ] 

    } 

  ] 

}); 

grid.appendTo('#Grid'); 

Note : When using remote data in grid, we have only knowledge about current page records. so we cannot get the entire data of Grid. So, we can calculate aggregate value from the current page records only when using customAggregate function. 

We have prepared a sample based on this for your reference.  

Sample: https://stackblitz.com/edit/r3i1wk?file=index.js 

Documentation link: https://ej2.syncfusion.com/javascript/documentation/grid/aggregates/#custom-aggregate 

Please get back to us if you need further assistance on this. 

Regards,  

Praveenkumar G