Python：不再使用时将变量设置为 None 的干净方法？

Question

Using excel from Python require to set all references to workbooks & excel app to None at the end to be sure it closes (using the API win32com.client).

At first I expected to be able to use the with keyword and include all the "clean up" code in the __exit__() function. But I still have references that needs to be cleaned up when I do it this way...

==> Is it possible to do it in a better way? Better = all the clean up code in packaged in the exit () function. (not using contextmanager has the same issue: Excel doesn't close if I use the "with" keyword instead of "inline" python )

example: I have to set wb & xlapp to None outside for the __exit__() function

class start_excel(object):
    def __init__(self):
        pass

    def __enter__(self):
        self.xlapp = win32.gencache.EnsureDispatch('Excel.Application')
        self.xlapp.Visible = False
        self.xlapp.Interactive = False

        return self.xlapp

    def __exit__(self, *args):
        self.xlapp.Quit()
        self.xlapp = None
        gc.collect()




class open_workbook(object):
    def __init__(self, xlapp, file_name):
        self.file_name = file_name
        self.xlapp = xlapp
     
    def __enter__(self):
        self.chemin_fichier = str(self.file_name)
        self.wb = self.xlapp.Workbooks.Open(self.chemin_fichier)
        
        return self.wb
 
    def __exit__(self, *args):
        self.wb.Close(SaveChanges=True)
        self.wb = None
        gc.collect()



with start_excel() as xlapp:
    # excel_constant = win32.constants
    with open_workbook(xlapp, file) as wb:
        wb.RefreshAll()
        xlapp.CalculateUntilAsyncQueriesDone()
        wb = None
    
    xlapp = None

thanks

Answer 1

Judging by this link , you can call xlapp.Application.Quit()