def METHOD_NAME(self, event=None):
    from PYME.IO.FileUtils import nameUtils
    fdialog = wx.FileDialog(None, 'Please select shift field to use ...',
                wildcard='Shift fields|*.sf', style=wx.FD_OPEN, defaultDir = nameUtils.genShiftFieldDirectoryPath())
    succ = fdialog.ShowModal()
    if (succ == wx.ID_OK):
        #self.ds = example.CDataStack(fdialog.GetPath().encode())
        #self.ds =
        sfFilename = fdialog.GetPath()
        self.image.mdh.setEntry('chroma.ShiftFilename', sfFilename)
        dx, dy = np.load(sfFilename)
        self.image.mdh.setEntry('chroma.dx', dx)
        self.image.mdh.setEntry('chroma.dy', dy)
        #self.md.setEntry('PSFFile', psfFilename)
        #self.stShiftFieldName.SetLabel('Shifts: %s' % os.path.split(sfFilename)[1])
        #self.stShiftFieldName.SetForegroundColour(wx.Colour(0, 128, 0))
        return True
    else:
        return False