postmessage_keypress.py

import ctypes
import ctypes.wintypes as wintypes
import time
import win32con

user32 = ctypes.CDLL('user32')

user32.MapVirtualKeyW.restype = wintypes.UINT
user32.MapVirtualKeyW.argtypes = (wintypes.UINT, wintypes.UINT)

user32.PostMessageW.restype = wintypes.BOOL
user32.PostMessageW.argtypes = (wintypes.HWND, wintypes.UINT, wintypes.WPARAM, wintypes.LPARAM)

user32.MapVirtualKeyA.restype = ctypes.c_uint32
user32.MapVirtualKeyA.argtypes = (ctypes.c_uint32, ctypes.c_uint32)

user32.FindWindowExW.restype = wintypes.HWND
user32.FindWindowExW.argtypes = (wintypes.HWND, wintypes.HWND, wintypes.LPWSTR, wintypes.LPWSTR)

user32.GetWindowTextW.restype = ctypes.c_int
user32.GetWindowTextW.argtypes = (wintypes.HWND, wintypes.LPWSTR, ctypes.c_int)

user32.GetClassNameW.restype = ctypes.c_int
user32.GetClassNameW.argtypes = (wintypes.HWND, wintypes.LPWSTR, ctypes.c_int)

user32.GetParent.restype = wintypes.HWND
user32.GetParent.argtypes = (wintypes.HWND,)

def enum_hwnds(parent=0):
    curr = 0
    while True:
        val = user32.FindWindowExW(parent, curr, None, None)
        if val:
            yield val
            curr = val
        else:
            break

def get_window_text(hwnd):
    buf = (ctypes.c_wchar * 1024)()
    n = user32.GetWindowTextW(hwnd, buf, 1024)
    return buf[:n]

def get_window_class(hwnd):
    buf = (ctypes.c_wchar * 1024)()
    n = user32.GetClassNameW(hwnd, buf, 1024)
    return buf[:n]

def press_key(hwnd, key):
    user32.PostMessageW(hwnd, win32con.WM_KEYDOWN, key, 0x0000001 | (user32.MapVirtualKeyW(key, 0) & 0xFF) << 16)
    user32.PostMessageW(hwnd, win32con.WM_KEYUP,   key, 0xC000001 | (user32.MapVirtualKeyW(key, 0) & 0xFF) << 16)

for hwnd in enum_hwnds():
    break
    title = get_window_text(hwnd)
    className = get_window_class(hwnd)
    parent = user32.GetParent(hwnd) or 0
    if parent or \
        not title or \
        className == 'Windows.Internal.Shell.TabProxyWindow' or \
        ((title, className) == ('Default IME', 'IME')):
        continue
    print('%.8x [%.8x] - %r / %r' % (hwnd, parent, title, className))

hwnd = user32.FindWindowExW(0, 0, 'vwr::CDesktopWin', None)
assert hwnd
print(hwnd)

for i in b'AAA':
    press_key(hwnd, i)
press_key(hwnd, win32con.VK_RETURN)