Как посылать нажатие клавиш в элемент управления

procedure SimulateKeyDown(Key: byte);
begin
  keybd_event(Key, 0, 0, 0);
end;

procedure SimulateKeyUp(Key: byte);
begin
  keybd_event(Key, 0, KEYEVENTF_KEYUP, 0);
end;

procedure SimulateKeystroke(Key: byte; extra: DWORD);
begin
  keybd_event(Key, extra, 0, 0);
  keybd_event(Key, extra, KEYEVENTF_KEYUP, 0);
end;

procedure SendKeys(s: string);
var
  i: integer;
  flag: bool;
  w: word;
begin
  {Get the state of the caps lock key}
  flag := not GetKeyState(VK_CAPITAL) and 1 = 0;
  {If the caps lock key is on then turn it off}
  if flag then
    SimulateKeystroke(VK_CAPITAL, 0);
  for i := 1 to Length(s) do
  begin
    w := VkKeyScan(s[i]);
    {If there is not an error in the key translation}
    if ((HiByte(w) $FF) and (LoByte(w) $FF)) then
    begin
      {If the key requires the shift key down - hold it down}
      if HiByte(w) and 1 = 1 then
        SimulateKeyDown(VK_SHIFT);
      {Send the VK_KEY}
      SimulateKeystroke(LoByte(w), 0);
      {If the key required the shift key down - release it}
      if HiByte(w) and 1 = 1 then
        SimulateKeyUp(VK_SHIFT);
    end;
  end;
  {if the caps lock key was on at start, turn it back on}
  if flag then
    SimulateKeystroke(VK_CAPITAL, 0);
end;

procedure TForm1.Button1Click(Sender: TObject);
begin
  {Toggle the cap lock}
  SimulateKeystroke(VK_CAPITAL, 0);
end;

procedure TForm1.Button2Click(Sender: TObject);
begin
  {Capture the entire screen to the clipboard}
  {by simulating pressing the PrintScreen key}
  SimulateKeystroke(VK_SNAPSHOT, 0);
end;

procedure TForm1.Button3Click(Sender: TObject);
begin
  {Capture the active window to the clipboard}
  {by simulating pressing the PrintScreen key}
  SimulateKeystroke(VK_SNAPSHOT, 1);
end;

procedure TForm1.Button4Click(Sender: TObject);
begin
  {Set the focus to a window (edit control) and send it a string}
  Application.ProcessMessages;
  Edit1.SetFocus;
  SendKeys('Delphi World is REALY BEST');
end;