How to add event to an inherited form event in Delphi?

Question

I explain, I have Fmodelo1 that has several standard functions, among them I have the creation of the Oncellclick event of a Dbgrid that is inherited to all the Formularios created from Fmodelo1, works beauty, now I need for example that the Fclientes that is inherited from Fmodelo1 has beyond the Oncellclick event heritage of Fmodelo1 its own event Cellclick added when clicked.

This is not happening because the event is being replaced by the Fmodelo1 event

I’ll try to put part of the code:

In the Onshow of Fmodelo1 I do several checks one of them is if exite Dbgrid in the Form, finding a Dbgrid I replace some events among them the Cellclick as abyss:

...
TDBGrid(Components[i]).OnCellClick := DBGridCellClick;
...

Dbgridcellclick is a Procedure with a standard routine for all Forms:

procedure TFmodelo1.DBGridCellClick(Column: TColumn);
begin
  if Column.PickList.Count > 0 then
  begin
    keybd_event(VK_F2, 0, 0, 0);
    keybd_event(VK_F2, 0, KEYEVENTF_KEYUP, 0);
    keybd_event(VK_MENU, 0, 0, 0);
    keybd_event(VK_DOWN, 0, 0, 0);
    keybd_event(VK_DOWN, 0, KEYEVENTF_KEYUP, 0);
    keybd_event(VK_MENU, 0, KEYEVENTF_KEYUP, 0);
  end;
end;

There in Fclientes has its own Cellclick with its particular routine, I can cancel in the Onshow the Fmodelo1 process with the line:

JvDBUltimGridClientes.OnCellClick := JvDBUltimGridClientesCellClick;

But I kind of wanted it to be something like this:

DBGridClientes.OnCellClick := DBGridCellClick + DBGridClientesCellClick;

In other words, he would take the events of Fmodelo1 + Fclientes

Answer 1

In that case you will have to override the class event TFModelo1 in TFClientes, would look something like this:

type
  TFClientes = class(TFModelo1)
  private
    FOnCellClick: TDBGridClickEvent;
    procedure SetOnCellClick(const Value: TDBGridClickEvent);

    procedure OnCellClick(Column: TColumn);
  public
    property OnCellClick: TDBGridClickEvent read FOnCellClick write SetOnCellClick; // Propriedade onde estará a procedure a ser executada

    constructor Create; reintroduce;
  end;

implementation

{ TFClientes }

constructor TFClientes.Create;
begin
  //Ao construir, você já passa a procedure desta classe pra ser executada
  inherited OnCellClick := FOnCellClick;
end;

procedure TFClientes.OnCellClick(Column: TColumn);
begin
  //Se foi passada alguma procedure para o OnCellClick, execute
  if (Assigned(FOnCellClick)) then
    FOnCellClick(Column);
end;

procedure TFClientes.SetOnCellClick(const Value: TDBGridClickEvent);
begin
  FOnCellClick := Value;
end;

Answer 2

You can call Handler the ancestor event:

procedure TFClientes.OnCellClick(Column: TColumn); begin inherited; //executa OnCellClick do FModelo1 ... //seu código do FClientes aqui end;