unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
  StdCtrls;

type
  TForm1 = class(TForm)
    Button1: TButton;
    Button2: TButton;
    Edit1: TEdit;
    procedure Button1Click(Sender: TObject);
  private
    { Private declarations }
  protected
    { Protected declarations }
  public
    { Public declarations }
  published
    { Published declarations }
    procedure MessageA(Sender: TObject);
    procedure MessageB(Sender: TObject);
    procedure MessageC(Sender: TObject);
  end;

var
  Form1: TForm1;

implementation

{$R *.DFM}

procedure TForm1.MessageA(Sender: TObject);
begin
  ShowMessage('A');
end;

procedure TForm1.MessageB(Sender: TObject);
begin
  ShowMessage('B');
end;

procedure TForm1.MessageC(Sender: TObject);
begin
  ShowMessage('C');
end;

procedure TForm1.Button1Click(Sender: TObject);
begin
  with TMethod(Button2.OnClick) do
  begin
     Data := Self;
     Code := Self.MethodAddress(Edit1.Text);
  end;
end;

end.