How do I access specific parameters of a wx.EVT_LISTBOX event?

Question

I am trying to design a GUI where one of the components is a wx.ListBox with multiple selection capability (style = wx.LB_MULTIPLE.) I also have another panel where I want to set the text to match the long description of the last item selected on the ListBox.

I am aware that I can bind the ListBox to a function in this manner: listbox_obj.Bind(wx.EVT_LISTBOX, self.set_description)

However, when I define the method...

def set_description(self, event):

...how do I extrapolate from the event parameter which item in the ListBox was the LAST one selected, and whether the item was selected or de-selected?

Answer 1

I think that you are going to have to track the data yourself.
For example:

import wx

class TestListBox(wx.Frame):
    def __init__(self, *args, **kwds):
        wx.Frame.__init__(self, *args, **kwds)
        self.OldSelections= []
        self.NewSelections = []
        self.aList = ['zero', 'one', 'two', 'three', 'four', 'five',
                      'six', 'seven', 'eight', 'nine', 'ten', 'eleven',
                      'twelve', 'thirteen', 'fourteen']
        self.lb = wx.ListBox(self, wx.NewId(), choices=self.aList, style=wx.LB_EXTENDED)
        self.lb.Bind(wx.EVT_LISTBOX, self.EvtMultiListBox)
        self.lb.SetSelection(0)
        self.Show()

    def EvtMultiListBox(self, event):
        self.NewSelections = self.lb.GetSelections()
        print('EvtMultiListBox: %s\n' % str(self.lb.GetSelections()))
        for i in self.NewSelections:
            if i not in self.OldSelections:
                print (self.aList[i],"was added")
        for i in self.OldSelections:
            if i not in self.NewSelections:
                print (self.aList[i],"was removed")
        self.OldSelections = self.NewSelections
        print("\n")

if __name__ == '__main__':
    app = wx.App()
    TestListBox(None)
    app.MainLoop()