__init__.py 文件源码

def getevents(clsid):
    """Determine the default outgoing interface for a class, given
    either a clsid or progid. It returns a class - you can
    conveniently derive your own handler from this class and implement
    the appropriate methods.

    This method relies on the classes produced by makepy. You must use
    either makepy or the gencache module to ensure that the
    appropriate support classes have been generated for the com server
    that you will be handling events from.

    Beware of COM circular references.  When the Events class is connected
    to the COM object, the COM object itself keeps a reference to the Python
    events class.  Thus, neither the Events instance or the COM object will
    ever die by themselves.  The 'close' method on the events instance
    must be called to break this chain and allow standard Python collection
    rules to manage object lifetimes.  Note that DispatchWithEvents() does
    work around this problem by the use of a proxy object, but if you use
    the getevents() function yourself, you must make your own arrangements
    to manage this circular reference issue.

    Beware of creating Python circular references: this will happen if your
    handler has a reference to an object that has a reference back to
    the event source. Call the 'close' method to break the chain.

    Example:

    >>>win32com.client.gencache.EnsureModule('{EAB22AC0-30C1-11CF-A7EB-0000C05BAE0B}',0,1,1)
    <module 'win32com.gen_py.....
    >>>
    >>> class InternetExplorerEvents(win32com.client.getevents("InternetExplorer.Application.1")):
    ...    def OnVisible(self, Visible):
    ...        print "Visibility changed: ", Visible
    ...
    >>>
    >>> ie=win32com.client.Dispatch("InternetExplorer.Application.1")
    >>> events=InternetExplorerEvents(ie) 
    >>> ie.Visible=1
    Visibility changed:  1
    >>>
    """

    # find clsid given progid or clsid
    clsid=str(pywintypes.IID(clsid))
    # return default outgoing interface for that class
    klass = gencache.GetClassForCLSID(clsid)
    try:
      return klass.default_source
    except AttributeError:
      # See if we have a coclass for the interfaces.
      try:
        return gencache.GetClassForCLSID(klass.coclass_clsid).default_source
      except AttributeError:
        return None

# A Record object, as used by the COM struct support