Use class variable in another class

问题

Greetings everyone,

I'm currently working on an app using Python and wxPython. In it I have a Dialog where several fields are filled in order to insert a "document" in a database. The layout of that Dialog consists basically of a wx.Notebook, with several "tabs", each containing some sort of fields.

# Dialog class
class NovoRegisto(wx.Dialog):
    def __init__(self,parent):
        wx.Dialog.__init__(self, parent, title='Registar Nova O.T.', size=(900,600))

        painel = wx.ScrolledWindow(self, -1, style=wx.VSCROLL|wx.HSCROLL)
        painel.SetScrollbars(0,30,0,500)
        notebook = wx.Notebook(painel)

        # create the page windows as children of the notebook
        pag1 = InfoOT(notebook)
        pag2 = Avaliacao(notebook)
        pag3 = Componentes(notebook)
        pag4 = Material(notebook)
        pag5 = OTsRelacionadas(notebook)

                          <...>
        # function to insert data in SQLite database
        def OnRegister(self,event):
                          <...>

# first tab class
class InfoOT(wx.Panel):
    def __init__(self, parent):
        wx.Panel.__init__(self, parent)

                          <...>

As you can see, I have a class for the Dialog itself (with a definition controlled by a "Register" button) and then a different class for each of the "tabs" of the notebook.

Now, in order to submit the data to the database, I must have access to the "tabs" variables in the "OnRegister" definition (which belongs to the Dialog's class). However, I still haven't found a way to do that.

Can anyone help me? Do I have to change my program's structure? I did it this way because it was the only way I managed to make the notebook work...

Thank you in advance

回答1:

Your "tabs" aren't class variables, they are local variables inside the function __init__. Also you don't want class variables, you want instance variables. To read and write instance variables you need to access them as attributes of self, for example self1.pag1, not by writing their name.

You need to distinguish between:

function local variables - variables that you assign within a function
class variables - class attributes that you access through the attribute operator (such as NovoRegisto.variable_name)
instance variables - instance attributes that you access by using the attribute operator on self (such as self.pag1).

You should probably read more about how Python classes should be used.

As an additional note, you'd most often want to use

super(InfoOT, self).__init__(parent)

over

wx.Panel.__init__(self, parent)

which is available in new-style classes (i.e. all classes that indirectly or directly inherit from the builtin object)

来源：https://stackoverflow.com/questions/4845834/use-class-variable-in-another-class

标签

python

oop

wxpython