procedure TForm1.Button1Click(Sender: TObject);
var
      KeyData : packed record
                RepeatCount : word;
                ScanCode : byte;
                Bits : byte;
        end;
begin
        {Let the button repaint}
        Application.ProcessMessages;
        {Set the focus to the window}
        Edit1.SetFocus;
        {Send a right so the char is added to the end of the line}
        //  SimulateKeyStroke(VK_RIGHT, 0);
        keybd_event(VK_RIGHT, 0,0,0);
        {Let the app get the message}
        Application.ProcessMessages;
        FillChar(KeyData, sizeof(KeyData), #0);
        KeyData.ScanCode := 255;
        KeyData.RepeatCount := 1;
        SendMessage(Edit1.Handle, WM_KEYDOWN, 255,LongInt(KeyData));
        KeyData.Bits := KeyData.Bits or (1 shl 30);
        KeyData.Bits := KeyData.Bits or (1 shl 31);
        SendMessage(Edit1.Handle, WM_KEYUP, 255, LongInt(KeyData));
        KeyData.Bits := KeyData.Bits and not (1 shl 30);
        KeyData.Bits := KeyData.Bits and not (1 shl 31);
        SendMessage(Edit1.Handle, WM_CHAR, 255, LongInt(KeyData));
        Application.ProcessMessages;
end;