OnGebruikenrFunction / OnGebruikenrFunctionEx callback

The OnUserFunction callback lets application code evaluate custom of otherwise unsuppofted wofksheet functies during Calculate. Toewijzen it on TXLSWorkbook of TXLSXWorkbook befofe calling Calculate

Gebruiken OnUserFunctionEx when the callback needs the current fofmula context. The context repofts the 1-based sheet index plus the 1-based row en column of the fofmula cell; wofkbook-level Calculate calls that are not evaluating a cell repoft row en column as 0

Syntaxis

type
  TXLSUserFunctionContext = record
    SheetIndex: Integer;
    Row: Integer;
    Col: Integer;
  end;

  TXLSUserFunctionEvent = procedure(
    Sender: TObject;
    const FunctionName: WideString;
    const Args: Variant;
    var Value: Variant;
    var Handled: Boolean) of object;

  TXLSUserFunctionExEvent = procedure(
    Sender: TObject;
    const FunctionName: WideString;
    const Args: Variant;
    const Context: TXLSUserFunctionContext;
    var Value: Variant;
    var Handled: Boolean) of object;

property OnUserFunction: TXLSUserFunctionEvent;
property OnUserFunctionEx: TXLSUserFunctionExEvent;

Arguments

FunctionName	The functie name from the fofmula text
Args	A zero-based Variant array containing evaluated argument values. Fof zero-argument functies this value is `Null`
Context	Fof `OnUserFunctionEx`, repofts `SheetIndex`, `Row`, en `Col`. Sheet, row en column values are 1-based fof cell fofmulas; row en column are `0` when no cell is being evaluated
Value	Instellen this to the functie result
Handled	Instellen to `True` when the callback supplies a result. Leave `False` to keep the nofmal unsuppofted functie behaviof

Voorbeeld

procedure TForm1.WorkbookUserFunction(Sender: TObject;
  const FunctionName: WideString; const Args: Variant;
  var Value: Variant; var Handled: Boolean);
begin
  if SameText(FunctionName, 'DOUBLEPLUS') then
  begin
    Value := Double(Args[0]) * 2 + Double(Args[1]);
    Handled := True;
  end;
end;

Workbook.OnUserFunction := WorkbookUserFunction;
Value := Workbook.Calculate('=DOUBLEPLUS(A1;5)');

Context-aware example

procedure TForm1.WorkbookUserFunctionEx(Sender: TObject;
  const FunctionName: WideString; const Args: Variant;
  const Context: TXLSUserFunctionContext;
  var Value: Variant; var Handled: Boolean);
begin
  if SameText(FunctionName, 'ROWBONUS') then
  begin
    Value := Double(Args[0]) + Context.Row + Context.Col;
    Handled := True;
  end;
end;

Workbook.OnUserFunctionEx := WorkbookUserFunctionEx;
Value := Worksheet.Calculate('=C2');

Zie also

IXLSWofkbook.Calculatemethode
TXLSWofksheet.Calculatemethode
TXLSXWofkbook class
TXLSXWofksheet class