//外部方法，只声明一个参数，此时按照标准的对象内部事件方法TNotifyEvent声明,此声明中，Sender则对应为产生该事件的对象指针。
procedure ExtClick1(Sender: TObject);
begin
  {asm
    mov eax,[edx+8]
    call showmessage
  end; }
  showmessage(TComponent(Sender).Name);
end;

//外部方法，声明两个参数,用来证明，对象在调用时候会传递一个Self指针，此时我们假设Frm是通过类对象传递过来的Self指针，而Sender为产生该事件的对象指针
procedure ExtClick(Frm: TObject;Sender: TObject);
begin
  {asm
    mov eax,[edx+8]
    call showmessage
  end; }
  showmessage(TComponent(Sender).Name);
  if Frm is TForm then
    TForm(Frm).Close
end;

//然后在 ‘指定调用’按扭事件中写代码：
procedure TForm1.Button1Click(Sender: TObject);
begin
   showmessage(TComponent(Sender).Name);
end;

//很显然运行的时候，点该按扭得到的是返回一个 消息内容为 ‘Button1’的对话框，这是调用Form1类的对象事件触发的方法。

//在调用 ‘调用Form类外部方法触发事件’ Click事件中写
procedure TForm1.Button2Click(Sender: TObject);
var
  ExtClickEvent: TNotifyEvent;
begin
  integer(@ExtClickEvent) := integer(@ExtClick1); 
//将ExtClickEvent地址指针指向外部函数ExtClick1方法的地址
  Button1.OnClick := ExtClickEvent;
//将该地址赋值给 Button1的OnClick事件替换以前的OnClick事件
end;
//另一个按扭写代码如下：
procedure TForm1.Button3Click(Sender: TObject);
begin
  Button1.OnClick := Button1Click;//还原为对象内触发事件函数
end;

procedure TForm1.Button4Click(Sender: TObject);
var
  CloseEvent: TCloseEvent;
begin
  integer(@CloseEvent) := integer(@MyCloseEvent);
  self.OnClose := CloseEvent;
end;

procedure MyCloseEvent(Frm: TForm;Sender: TObject;var Action: TCloseAction);
begin
  showmessage(Frm.Name+'窗体外部方法调用，不允许关闭窗体！');
  Action := caNone;
end;

procedure TForm1.SetEvent(Event: pointer);
asm
  push ebx                //保护Ebx
  mov ebx,eax    //将当前的eax的值，先用ebx保存起来，eax中保存的为Form的开始地
  mov eax,edx    //将Event指针的值给EAX
  mov [ebx+$2d8],eax   //将Eax的值分别写进其高位和低位 
  mov eax,[edx+4]    
  mov [ebx+$2d4],eax
  pop ebx
end;

procedure ReSetObjEvent(OldEventAddress: Pointer;NewEventValue: pointer);
var
  gg: integer;
  sd: pinteger;
begin
sd := OldEvent;
  gg := integer(NewEvent);
  sd^:=gg;
end;

procedure FrmClose(Frm: TForm;Sender: TObject;Var Action: TCloseAction);
begin
   showmessage('调用外部方法，不许关闭！');
   action := canone;
end;

procedure TForm1.BitBtn1Click(Sender: TObject);
begin
  ReSetObjEvent(@(integer(@self.OnClose)),@frmClose);
end;

procedure TForm1.Button4Click(Sender: TObject);
var
  CloseEvent: TCloseEvent;
begin
  integer(@CloseEvent) := integer(@MyCloseEvent);
  self.OnClose := CloseEvent;
end;

TMethod = record
  Code, Data: Pointer;
end;

procedure MyClick(Self: TObject; Sender: TObject);
begin
  // 第一个参数是虚拟的
  ShowMessage(Format('Self: %d, Sender: %s', [Integer(Self), Sender.ClassName]));
end;

procedure TForm1.FormCreate(Sender: TObject);
var
  M: TMethod;
begin
  M.Code := @MyClick;
  M.Data := Pointer(325); // 随便取的数
  btn1.OnClick := TNotifyEvent(M);
end;

constructor TLanguages.Create;
type
  TCallbackThunk = packed record
    POPEDX: Byte;
    MOVEAX: Byte;
    SelfPtr: Pointer;
    PUSHEAX: Byte;
    PUSHEDX: Byte;
    JMP: Byte;
    JmpOffset: Integer;
  end;
var
  Callback: TCallbackThunk;
begin
  inherited Create;
  Callback.POPEDX := $5A;
  Callback.MOVEAX := $B8;
  Callback.SelfPtr := Self;
  Callback.PUSHEAX := $50;
  Callback.PUSHEDX := $52;
  Callback.JMP     := $E9;
  Callback.JmpOffset := Integer(@TLanguages.LocalesCallback) - Integer(@Callback.JMP) - 5;
  EnumSystemLocales(TFNLocaleEnumProc(@Callback), LCID_SUPPORTED);
end;

BOOL CALLBACK EnumLocalesProc(
    LPTSTR lpLocaleString         // pointer to locale identifier string
);

  TLanguages = class
    ...
    function LocalesCallback(LocaleID: PChar): Integer; stdcall;
    ...
  end;

prcoedure CallbackThunk;
asm
  // 取出 lpLocaleString 参数到 EDX 寄存器
  // CALLBACK EnumLocalesProc 是 stdcall 调用，参数在堆栈中
  POP EDX
  // 将 Self 对象传给 EAX 寄存器
  MOV EAX Self
  // stdcall 调用，将 Self 作为第一个参数压栈
  PUSH EAX
  // 将 lpLocaleString 作为第二个参数压栈
  PUSH EDX
  // 用相对跳转指令跳转到 TLanguages.LocalesCallback 入口地址
  JMP TLanguages.LocalesCallback
end;

var
  FTempLanguages: TLanguages;

function EnumLocalesCallback(LocaleID: PChar): Integer; stdcall;
begin
  Result := FTempLanguages.LocalesCallback(LocaleID);
end;

constructor TLanguages.Create;
begin
  inherited Create;
  FTempLanguages := Self;
  EnumSystemLocales(@EnumLocalesCallback, LCID_SUPPORTED);
end;

function MakeObjectInstance(Method: TWndMethod): Pointer;
var
  ...
begin
  if InstFreeList = nil then
  begin
    Block := VirtualAlloc(nil, PageSize, MEM_COMMIT, PAGE_EXECUTE_READWRITE);
    ...
end;

if Assigned(FOnClick) then
  FOnClick(Self);

if Assigned(FOnClick) then
  FOnClick(Self);

procedure ReSetObjEvent(OldEventAddr: pointer;NewEventValue: pointer;ReSetObject: TObject);
begin
TMethod(OldEventAddr^).Code := NewEventValue;
TMethod(OldEventAddr^).Data := ReSetObject;
end;
//参数一： 指定为 存放事件指针的内存地址值的地址指针，所以为一个指针的指针
//参数二： 指定为新的事件函数地址指针
//参数三： 指定为重设事件的修改者,用来隐射对象方法的隐含参数Self

//调用方法：
  ReSetObjEvent(@integer(@self.OnClose),@MyCloseEvent,self);

//例：

procedure MyCloseEvent(ClassSend: TObject;Sender: TObject;var Action: TCloseAction );
begin
    action := canone;
    showmessage(TComponent(Sender).Name+'触发,不许关闭');
    showmessage(TComponent(ClassSend).Name);
end;

procedure TForm1.Button1Click(Sender: TObject);
begin
  ReSetObjEvent(@integer(@self.OnClose),@MyCloseEvent,self);
end;