Question

I have to write a script to emulate some keyboard event in a different program in background.This is my code：

pwin = win32ui.FindWindow(None,r'someprograme')
pwin.SendMessage(win32con.WM_KEYDOWN,18)
pwin.SendMessage(win32con.WM_KEYDOWN,68)
pwin.SendMessage(win32con.WM_KEYUP,18)
pwin.SendMessage(win32con.WM_KEYUP,68)
pwin.SendMessage(win32con.WM_KEYDOWN,13)
pwin.SendMessage(win32con.WM_KEYUP,13)

But it seems nothing happened.So what should i do?I’ve tried PostMessage func it seems it still can not do it.

Answer 1

After a quick look at the WM_KEYDOWN docs:

Posted to the window with the keyboard focus when a nonsystem key is pressed. A nonsystem key is a key that is pressed when the ALT key is not pressed.

But looking up your keycodes, you’re trying to send ALT-D (followed by ENTER, which is fine). It sounds like you’re trying to drive the menus; if that’s what you want to do, WM_KEYDOWN is not the way to do it.

The problem is that keyboard menu navigation is driven by Windows, not by the app (except for a handful of apps that override normal menu processing, like some versions of Visual Studio). When you’re looking at Notepad, and you hit ALT-F to open the File menu, the Notepad code gets a bunch of menu-related messages (WM_INITMENU, etc.), not the keystrokes.

If you use a WM spy program (I think the free Visual Studio Express still comes with Spy++ and ManagedSpy, but if not, search for an equivalent), you can see what the application is actually seeing when you drive it with the keyboard, and then you can figure out how to emulate that from your Python script.

On top of everything else, depending on how the program is written, it may not accept keystrokes when it doesn’t have focus.

By the way, if you’re just getting started with Windows GUI automation, you might want to look at something higher level, like pywinauto. That way, you don’t have to work out what menu-related messages to send to open the Data menu; you just do something like app.Foo.MenuSelect('Data').