IncDay returns the given date, incremented by the number of days given as the ANumberOfDays parameter.

ANumberOfDays can be negative, to return a date earlier by the specified number of days.

Declaration: Function IncDay(const AValue: TDateTime; const ANumberOfDays: Integer): TDateTime;

This is a simple example.

procedure OnMapEvent(var Value:Variant);
begin
//Returns a date incremented by 10 days
Value := IncDay(Date, 10);
end;