[wxPython-users] using lambda to pass args to event function

[Christopher Barker]

TiNo wrote:
>> def makeArgsHandler(handler, arg):
>>      return lambda event: handler(event, arg)

> 2006/11/20, Christopher Barker <Chris.Barker at noaa.gov>:
>> however, for an example this simple, you may be able to make use us
>> default arguments:
>>
>>      self.Bind(wx.EVT_BUTTON,
>>                lambda event: handler(event, arg=current_arg),
>>                id = ID_PKL_BUTTON)
>>
>> now arg will get set to whatever current_arg is when that Bind call is
>> executed -- i.e. in the Window __init__, usually.
> 
> I use it this way :D :
> --------------------------------------
> #Set button events
> self.Bind(wx.EVT_BUTTON,
>          makeArgsHandler(controller.PopulateMainList,'pkl'),
>          id=ID_PKL_BUTTON)

which could be:
self.Bind(wx.EVT_BUTTON,
           lambda event: controller.PopulateMainList(event, arg='pkl'),
           id=ID_PKL_BUTTON)

Thus relieving you of the need to have the makeArgsHandler() function at 
all.

> referencing to the button itself is not that easy. Bind is called in
> main class. Button is located in gui class, in a subclass, in a panel,
> in a sizer, etc. I find this easier. If I decide to put the button in
> another panel I don't have to change these binds.

That does sound like a flexible structure, but:

I see a lot of explicit naming: ID_PKL_BUTTON, 'pkl', etc. It looks like 
there could be some cleaning up there. Maybe all these buttons should go 
in a list or dict, rather than keeping them all around my name.

Also, for me, Event binding is very much a GUI function -- why not have 
it with the GUI code?

Who knows, I'd have to see the whole app structure to be sure.

-Chris

-- 
Christopher Barker, Ph.D.
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