private List <Set> LoadStructurings()
        {
            OpenFileDialog _dlg = new OpenFileDialog();

            //_dlg.InitialDirectory = GetContentFolder();
            _dlg.Filter      = "ARFF Documents (*.arff)|*.arff";
            _dlg.FilterIndex = 1;
            _dlg.Multiselect = true;

            List <Set> sets = new List <Set>();

            if (_dlg.ShowDialog() == System.Windows.Forms.DialogResult.OK)
            {
                try
                {
                    foreach (string filename in _dlg.FileNames)
                    {
                        ArffLoader _arffLoader = new ArffLoader(filename);

                        _arffLoader.SetSource(filename);
                        Set s = _arffLoader.Load();

                        sets.Add(s);
                    }
                }
                catch (Exception _ex)
                {
                    System.Windows.MessageBox.Show("Corrupt file, try with another.", "Error", MessageBoxButton.OK, MessageBoxImage.Error);

                    return(null);
                }

                return(sets);
            }
            else
            {
                return(null);
            }
        }