Delphi - Get Msg type of button on another process

Question

How i can know what is the Msg type of a button on another process e.g. WM_COMMAND

My goal is

I want to click that button even if its disabled. I know i can simply enable the targeted button using EnableWindow then using

PostMessage(hButton, WM_KEYDOWN, VK_RETURN, 0);

The problem is if there is a thread to validate something e.g.

if TRUE then 
buttonX.enabled := True
else
buttonX.enabled := False;

Is it possible to click that button even if the thread is running like this.

PostMessage(hTargetApp, WM_COMMAND, XXXX, 0);

This is my DLL

function WindowProcMain(hWnd: HWND; Msg: UINT; wParam: WPARAM; lParam: LPARAM): Longint; stdcall;
begin
  case Msg of
    WM_COMMAND:MessageBoxW(HWND_DESKTOP, PChar('The WM_COMMAND code is: '+IntToStr(wParam)), 'WM_COMMAND', MB_OK);
  end;
  Result := CallWindowProc(MainWndProc, hWnd, Msg, wParam, lParam);
end;

I have inject it to a process have this buton

procedure TMainForm.btn1Click(Sender: TObject);
begin
  ShowMessage('You Click Me');
end;

But nothing is appears

Please correct if my understanding is wrong, And point me in the right direction.

Answer 1

The correct way to simulate a button click with a WM_COMMAND message is like this:

PostMessage(GetParent(hButton), WM_COMMAND, MAKEWPARAM(GetDlgCtrlID(hButton), BN_CLICKED), hButton);

However, that is no guarantee that the button's click handler will be called if the button window is actually disabled. For a VCL TButton component, it will be called. But if you inject your code into a non-VCL process, who knows what rules it will follow.