Question

我在使用某些Windows服务中的事件时遇到问题（我无法访问源代码，我只有文档）。其中一个事件（在文档中）被定义为（C＃）：

public event BarcodeScanEventHandler OnBarcodeScanned

BarcodeScanEventHandler：

public delegate void BarcodeScanEventHandler( Object sender, BarcodeScanEventArgs args )

让我告诉你一个最小化的例子：

import win32com.client
cls="FooService"

api = win32com.client.Dispatch(cls)

class ApiEvents:
    def OnBarcodeScanned(self, value): #doesnt matter if its OnBarcodeScanned(self) or OnBarcodeScanned(self, value1, value2)
        print(" * Barcode scanned!")

api.Initialize()
events = win32com.client.WithEvents(api, ApiEvents)

什么引发错误：

  File "minevents", line 14, in <module>
    events = win32com.client.WithEvents(api, ApiEvent
  File "C:\Python27\lib\site-packages\win32com\client
 WithEvents
    raise ValueError("This COM object does not suppor
ValueError: This COM object does not support events.

我试图谷歌它，但没有有用的信息。之后我尝试了另一个库comtypes，其代码如下：

import comtypes.client
api = comtypes.clientCreateObject("FooService")
comtypes.client.ShowEvents(api)

但它会引发错误：

  File "<pyshell#5>", line 1, in <module>
    comtypes.client.ShowEvents(api)
  File "C:\Python27\lib\site-packages\comtypes\client\_events.py", line 218, in ShowEvents
    return comtypes.client.GetEvents(source, sink=EventDumper(), interface=interface)
  File "C:\Python27\lib\site-packages\comtypes\client\_events.py", line 193, in GetEvents
    interface = FindOutgoingInterface(source)
  File "C:\Python27\lib\site-packages\comtypes\client\_events.py", line 62, in FindOutgoingInterface
    interface = comtypes.com_coclass_registry[clsid]._outgoing_interfaces_[0]
AttributeError: type object 'FooService' has no attribute '_outgoing_interfaces_'

我也试过了help(api)并且有一些有趣的功能：

 |  add_OnBarcodeScanned(...)
 |  remove_OnBarcodeScanned(...)

我试图致电add_OnBarcodeScanned：

class BarcodeScanned(object):
    def QueryInterface(self, value):
        help(value)

barcodeScanned = BarcodeScanned()
api.add_OnBarcodeScanned(barcodeScanned)

是什么让我IUnknown：

class IUnknown(__builtin__.object)
 |  The most basic COM interface.
 |  
 |  Each subclasses of IUnknown must define these class attributes:
 |  
 |  _iid_ - a GUID instance defining the identifier of this interface
 |  
 |  _methods_ - a list of methods for this interface.
 |  
 |  The _methods_ list must in VTable order.  Methods are specified
 |  with STDMETHOD or COMMETHOD calls.
 |  
 |  Methods defined here:
 |  
 |  AddRef(self)
 |      Increase the internal refcount by one and return it.
 |  
 |  QueryInterface(self, interface, iid=None)
 |      QueryInterface(interface) -> instance
 |  
 |  Release(self)
 |      Decrease the internal refcount by one and return it.
 |  
 |  ----------------------------------------------------------------------
 |  Data descriptors defined here:
 |  
 |  __dict__
 |      dictionary for instance variables (if defined)
 |  
 |  __weakref__
 |      list of weak references to the object (if defined)
 |  
 |  ----------------------------------------------------------------------
 |  Data and other attributes defined here:
 |  
 |  __metaclass__ = <class 'comtypes._cominterface_meta'>
 |      Metaclass for COM interfaces.  Automatically creates high level
 |      methods from COMMETHOD lists.

现在我不知道该怎么办。难道我做错了什么？但是您应该知道以下所有代码都适用于InternetExplorer.Application。这项服务有问题吗？或者您是否知道如果触发事件，如何使用方法add_OnBarcodeScanned来调用我的python方法/类？

感谢您的时间。

无法通过python使用COM服务事件

0 个答案: