Send some keys to inactive window with python

Question

I\'m tryin to send some keys to inactive window/process/programm (win32/64) using python. Already read about pywinauto and SendKeys, but both of them activate window before

Answer 1

This is a really old post but there has not been an answer here, I was looking for something exactly like this, and I had spend 6 hours going through Stackoverflow, and ended up just reading all the C documentation because it was more useful.

#you will need the win32 libraries for this snippet of code to work, Links below
import win32gui
import win32con
import win32api
from time import sleep

#[hwnd] No matter what people tell you, this is the handle meaning unique ID, 
#["Notepad"] This is the application main/parent name, an easy way to check for examples is in Task Manager
#["test - Notepad"] This is the application sub/child name, an easy way to check for examples is in Task Manager clicking dropdown arrow
#hwndMain = win32gui.FindWindow("Notepad", "test - Notepad") this returns the main/parent Unique ID
hwndMain = win32gui.FindWindow("Notepad", "test - Notepad")

#["hwndMain"] this is the main/parent Unique ID used to get the sub/child Unique ID
#[win32con.GW_CHILD] I havent tested it full, but this DOES get a sub/child Unique ID, if there are multiple you'd have too loop through it, or look for other documention, or i may edit this at some point ;)
#hwndChild = win32gui.GetWindow(hwndMain, win32con.GW_CHILD) this returns the sub/child Unique ID
hwndChild = win32gui.GetWindow(hwndMain, win32con.GW_CHILD)

#print(hwndMain) #you can use this to see main/parent Unique ID
#print(hwndChild)  #you can use this to see sub/child Unique ID

#While(True) Will always run and continue to run indefinitely
while(True):
    #[hwndChild] this is the Unique ID of the sub/child application/proccess
    #[win32con.WM_CHAR] This sets what PostMessage Expects for input theres KeyDown and KeyUp as well
    #[0x44] hex code for D
    #[0]No clue, good luck!
    #temp = win32api.PostMessage(hwndChild, win32con.WM_CHAR, 0x44, 0) returns key sent
    temp = win32api.PostMessage(hwndChild, win32con.WM_CHAR, 0x44, 0)

    #print(temp) prints the returned value of temp, into the console
    print(temp)
    #sleep(1) this waits 1 second before looping through again
    sleep(1)

I've seen posts all over to use

hwndEdit = win32gui.FindWindowEx(hwndMain, hwndChild, "Edit", "test - Notepad");

but I could never figure it out. In addition to that all documentation on Microsoft's site is vary ambiguous, So I've added my own of how I understand it.

That should get you started and should be helpful for others. If anyone else had revisions let me know.

Win32 Python Library