TVirtualDataTableState.TryAggregate Method
This method is used by the "AGGREGATE" tag in a FlexCel report to calculate the maximum/minimum/average/etc of the values in the table. If you don't implement this method, FlexCel will still calculate those values by looping through the dataset, but if you have a faster way to do it (like with a "select max(field) from table") then implement this method and return true.
Syntax
Unit: FlexCel.Report
function TVirtualDataTableState.TryAggregate(const aggregateType: TAggregateType; const colIndex: Integer; out resultValue: TCellValue): Boolean; virtual;Parameters
| <-> | Parameter | Type | Description |
|---|---|---|---|
| const | aggregateType | TAggregateType | Which operation to do on the dataset. (Max/Min/etc) |
| const | colIndex | Integer | Index of the field in which we want to aggregate. |
| out | resultValue | TCellValue | Returns the result of the operation in the dataset. It should be null, a double or a datetime. |
Returns
True if this method is implemented, false if not. Note that even if we return false here, FlexCel will still calculate the aggregate by looping through all the records.