def OnSaveAs(self, event):

            with wx.FileDialog(self, "Save XYZ file", wildcard="XYZ files (*.xyz)|*.xyz",
                               style=wx.FD_SAVE | wx.FD_OVERWRITE_PROMPT) as fileDialog:

                if fileDialog.ShowModal() == wx.ID_CANCEL:
                    return     # the user changed their mind

                # save the current contents in the file
                pathname = fileDialog.GetPath()
                try:
                    with open(pathname, 'w') as file:
                        self.doSaveData(file)
                except IOError:
                    wx.LogError("Cannot save current data in file '%s'." % pathname)