How to send keystrokes to a window?

Question

im using keybd_event(); and i want use SendMessage(); to send keystroke to notepad, can this be done?

Answer 1

keybd_event() has been superseded with SendInput(), so it's best to use that. Here is some example code to do what you have asked. You can either directly edit the Notepad window's edit control using SendMessage(), or you can use SendInput() to synthesise keystrokes to be sent to the window.

Using SendInput():

int SendKeystrokesToNotepad( const TCHAR *const text )
{
    INPUT *keystroke;
    UINT i, character_count, keystrokes_to_send, keystrokes_sent;
    HWND notepad;

    assert( text != NULL );

    //Get the handle of the Notepad window.
    notepad = FindWindow( _T( "Notepad" ), NULL );
    if( notepad == NULL )
        return 0;

    //Bring the Notepad window to the front.
    if( !SetForegroundWindow( notepad ) )
        return 0;

    //Fill in the array of keystrokes to send.
    character_count = _tcslen( text );
    keystrokes_to_send = character_count * 2;
    keystroke = new INPUT[ keystrokes_to_send ];
    for( i = 0; i < character_count; ++i )
    {
        keystroke[ i * 2 ].type = INPUT_KEYBOARD;
        keystroke[ i * 2 ].ki.wVk = 0;
        keystroke[ i * 2 ].ki.wScan = text[ i ];
        keystroke[ i * 2 ].ki.dwFlags = KEYEVENTF_UNICODE;
        keystroke[ i * 2 ].ki.time = 0;
        keystroke[ i * 2 ].ki.dwExtraInfo = GetMessageExtraInfo();

        keystroke[ i * 2 + 1 ].type = INPUT_KEYBOARD;
        keystroke[ i * 2 + 1 ].ki.wVk = 0;
        keystroke[ i * 2 + 1 ].ki.wScan = text[ i ];
        keystroke[ i * 2 + 1 ].ki.dwFlags = KEYEVENTF_UNICODE | KEYEVENTF_KEYUP;
        keystroke[ i * 2 + 1 ].ki.time = 0;
        keystroke[ i * 2 + 1 ].ki.dwExtraInfo = GetMessageExtraInfo();
    }

    //Send the keystrokes.
    keystrokes_sent = SendInput( ( UINT )keystrokes_to_send, keystroke, sizeof( *keystroke ) );
    delete [] keystroke;

    return keystrokes_sent == keystrokes_to_send;
}

Using SendMessage():

int SendKeystrokesToNotepad( const TCHAR *const text )
{
    HWND notepad, edit;

    assert( text != NULL );

    //Get the handle of the Notepad window.
    notepad = FindWindow( _T( "Notepad" ), NULL );
    if( notepad == NULL )
        return 0;

    //Get the handle of the Notepad window's edit control.
    edit = FindWindowEx( notepad, NULL, _T( "Edit" ), NULL );
    if( edit == NULL )
        return 0;

    SendMessage( edit, EM_REPLACESEL, ( WPARAM )TRUE, ( LPARAM )text );
    return 1;
}

I hope that helps.