Re: pywintypes.com_error: (-2147221005, 'Invalid class string', None, None)

Thank you for your response I will to that .

But my issue is not only with Quickopc , I have installed OpenOPC in that also I’m getting same error

My code:

import OpenOPC

opc = OpenOPC.client()

Output Error:

Traceback (most recent call last):

File "C:\Users\Saleem\AppData\Local\Programs\Python\Python38-32\lib\site-packages\win32com\client\dynamic.py", line 89, in _GetGoodDispatch

IDispatch = pythoncom.connect(IDispatch)

pywintypes.com_error: (-2147221005, 'Invalid class string', None, None)

During handling of the above exception, another exception occurred:

Traceback (most recent call last):

File "C:\Users\Saleem\AppData\Local\Programs\Python\Python38-32\lib\site-packages\OpenOPC.py", line 167, in __init__

self._opc = win32com.client.gencache.EnsureDispatch(c, 0)

File "C:\Users\Saleem\AppData\Local\Programs\Python\Python38-32\lib\site-packages\win32com\client\gencache.py", line 527, in EnsureDispatch

disp = win32com.client.Dispatch(prog_id)

File "C:\Users\Saleem\AppData\Local\Programs\Python\Python38-32\lib\site-packages\win32com\client\__init__.py", line 95, in Dispatch

dispatch, userName = dynamic._GetGoodDispatchAndUserName(dispatch,userName,clsctx)

File "C:\Users\Saleem\AppData\Local\Programs\Python\Python38-32\lib\site-packages\win32com\client\dynamic.py", line 114, in _GetGoodDispatchAndUserName

return (_GetGoodDispatch(IDispatch, clsctx), userName)

File "C:\Users\Saleem\AppData\Local\Programs\Python\Python38-32\lib\site-packages\win32com\client\dynamic.py", line 91, in _GetGoodDispatch

IDispatch = pythoncom.CoCreateInstance(IDispatch, None, clsctx, pythoncom.IID_IDispatch)

pywintypes.com_error: (-2147221005, 'Invalid class string', None, None)

During handling of the above exception, another exception occurred:

Traceback (most recent call last):

File ".\test.py", line 7, in <module>

opc = OpenOPC.client()

File "C:\Users\Saleem\AppData\Local\Programs\Python\Python38-32\lib\site-packages\OpenOPC.py", line 173, in __init__

raise OPCError(error_msg)

OpenOPC.OPCError: Dispatch: Invalid class string

OpenOPC I have installed from here https://pypi.org/project/OpenOPC-Python3x/ and how to use examples is here http://openopc.sourceforge.net/api.html .

In my Case pywin32 is not matching with the version python I’m using .

Python version I’m using downloaded from here : https://www.python.org/ftp/python/3.8.5/python-3.8.5.exe

Pywin32 downloaded from here : https://github.com/mhammond/pywin32/releases/download/b228/pywin32-228.win32-py3.8.exe

Can you please suggest me the versions which I can use to solve this errors , because the same version I’m using in another windows laptop there I’m not getting this errors.

Thanks & Regards,

Saleem.

From: Tim Roberts
Sent: Wednesday, September 9, 2020 12:16 AM
To: [email protected]
Subject: Re: [python-win32] pywintypes.com_error: (-2147221005, 'Invalid class string', None, None)

Shaik Saleem Basha wrote:

> When I downloaded install python by default it installed 32bit

> version only so pywin32 also I installed 32bit only

> Quicopc library is installed

If QuickOPC is a 64-bit component, then you need to call it from a

64-bit process. This is not always an easy thing to determine. If a

company wants to support both 32-bit and 64-bit processes, then it has

to install two different COM servers. I suggest you describe your

problem to the QuickOPC folks; they would know right away if this were

the issue.

--

Tim Roberts, [email protected]

Providenza & Boekelheide, Inc.

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