Send CTRL+V to a ParentWindow in Delphi with SendMessage

Question

I've been trying to send keystrokes to a notepad window in Delphi. That's the code I have so far:

program Project1;

{$APPTYPE CONSOLE}

{$R *.res}

uses
  System.SysUtils,
  windows,
  messages;

var
  H : HWND;

begin
  H := FindWindowA(NIL, 'Untitled - Notepad');
  if H <> 0 then begin
    SendMessage(H, WM_KEYDOWN, VK_CONTROL, 1);
    SendMessage(H, WM_KEYDOWN, MapVirtualKey(ord('v'), 0), 1);
    SendMessage(H, WM_KEYUP, MapVirtualKey(ord('v'), 0), 1);
    SendMessage(H, WM_KEYUP, VK_CONTROL, 1);
  end;
end.

I've also found this example:

program Project1;

{$APPTYPE CONSOLE}

{$R *.res}

uses
  System.SysUtils,
  windows,
  messages;

var
  H : HWND;
  I : Integer;
  s : String;

begin
  h := FindWindowA(NIL, 'Untitled - Notepad');
  if h <> 0 then
  begin
    h := FindWindowEx(h, 0, 'Edit', nil);
    s := 'Hello';
    for i := 1 to Length(s) do
    SendMessage(h, WM_CHAR, Word(s[i]), 0);
    PostMessage(h, WM_KEYDOWN, VK_RETURN, 0);
    PostMessage(h, WM_KEYDOWN, VK_SPACE, 0);
  end;
end.

How can I simulate/Send CTRL+V to a Parentwindow so it would also work with other applications? Not every application has the same ClassNames and controls as notepad.

Answer 1

If you switch SendMessage() to PostMessage(), it will work:

uses
  Winapi.Windows, Winapi.Messages;

procedure PasteTo(const AHWND: HWND);
begin
  PostMessage(AHWND, WM_PASTE, 0, 0);
end;

var
  notepad_hwnd, notepad_edit_hwnd: HWND;

begin
  notepad_hwnd := FindWindow(nil, 'Untitled - Notepad');
  if notepad_hwnd <> 0 then
  begin
    notepad_edit_hwnd := FindWindowEx(notepad_hwnd, 0, 'Edit', nil);
    if notepad_edit_hwnd <> 0 then
      PasteTo(notepad_edit_hwnd);
  end;
end.

According to this thread, I beleive you cannot use SendMessage()/PostMessage() to send state of key modifiers (CTRL in this case), and that your only option is to go with SendInput(), but that will work only on window that currently has focus.