在 Microsoft Word 实例上的 python 中使用 AccessibleObjectFromWindow

Question

我正在尝试使用 python 操作特定的已打开、未保存（因此没有路径）Word 文档 (*.doc)。如果只打开一个 Word 实例，则操作效果很好，但是多个实例会产生一些困难，请参考 SO 问题 Word VBA and Multiple Word Instances。

我在 C# (How to access Microsoft Word existing instance using late binding) 和 VB.NET (Multiple Instances of Applications) 中找到了一些关于处理此问题的参考资料，并设法将它们翻译成 python。这是我现在的位置：

import win32com.client as win32
import win32gui
#GUID class from http://svn.python.org/projects/ctypes/tags/release_0_2/ctypes/comtypes/GUID.py
from GUID import GUID
from ctypes import oledll
from ctypes import byref
from comtypes import POINTER
from comtypes.automation import IDispatch

#Use win32 functions to get the handle of the accessible window
#of the desired Word instance.  Specific code not relevant here, 
#but I'll end up with an integer such as:
hwnd = 2492046

OBJID_NATIVEOM = 0xffffff0
IID_IDispatch = byref(GUID("{00020400-0000-0000-C000-000000000046}"))
p = POINTER(IDispatch)()
oledll.oleacc.AccessibleObjectFromWindow(hwnd, OBJID_NATIVEOM, IID_IDispatch, p)

运行时，返回错误信息：

  File "wordtest.py", line 55, in <module>
    oledll.oleacc.AccessibleObjectFromWindow(hwnd, OBJID_NATIVEOM, IID_IDispatch, p)
  File "_ctypes/callproc.c", line 945, in GetResult
WindowsError: [Error -2147024809] The parameter is incorrect

非常感谢您在修复此错误方面的任何帮助！

Answer 1

通过 NVDA (Non-Visual Desktop Access) 的 GitHub 代码搜索显示我用于 OBJID_NATIVEOM 的值不正确，我需要将指针包装在 byref() 中，并且有一个更简单的方法来获取IDispatch 的 GUID：

#Part of the pywin32 package that must be installed with the pywin32
#installer:
import win32gui

from ctypes import oledll
from ctypes import byref

#installed by easy_install comtypes
from comtypes import POINTER
from comtypes.automation import IDispatch
import comtypes.client.dynamic as comDy

#Handle integer hwnds[0] from code at 
#http://stackoverflow.com/questions/33901597/getting-last-opened-ms-word-document-object

OBJID_NATIVEOM = -16
p = POINTER(IDispatch)()
oledll.oleacc.AccessibleObjectFromWindow(hwnds[0], OBJID_NATIVEOM,
    byref(IDispatch._iid_), byref(p))

window = comDy.Dispatch(p)
word = window.application
cert = word.Documents(1)