Python: How to get the text label from another program window?

Question

I want to read text labels from another program, with Python. I think I have to use WM_GETTEXT, but I don't know how and I couldn't find anything on the internet. My program gets the active window, but doesn't read the text labels. So I hope that somebody can help me.

EDIT: I have added the buffer and SendMessage Part. I can get the text from Editor for example, but not from the program I am trying to get the text labels from.

I have the following code, which I found here on stackoverflow(Get text from popup window):

import win32gui
import time

while True:
    window = win32gui.GetForegroundWindow()
    title = win32gui.GetWindowText(window)
    if 'GLS Exportdatei' in title:
        control = win32gui.FindWindowEx(window, 0, 'static', None)
        buffer = win32gui.PyMakeBuffer(20)
        length = win32gui.SendMessage(control, win32con.WM_GETTEXT, 20, buffer)

        result = buffer[:length]
        print result
        time.sleep(1)

Answer 1

If the text of your window has more than 20 characters, then the buffer you have created is too small. Try expanding it to more than you're likely to need:

buffer = win32gui.PyMakeBuffer(255)
length = win32gui.SendMessage(control, win32con.WM_GETTEXT, 255, buffer)

If you want to get to the controls within the main window, then use EnumChildWindows, passing the handle of the parent window. You may need to do this recursively.

Answer 2

win32gui.PyMakeBuffer has been deprecated. Also, buffer is a builtin function, so don't use it as a variable name.

Instead, just do this:

buf = " " * 255
length = win32gui.SendMessage(control, win32con.WM_GETTEXT, 255, buf)
result = buf[:length]