private void btnOpenData_Click(object sender, RoutedEventArgs e)
        {
            try
            {
                drawingPad.Children.Clear();
                lstPoint.Clear();
                dataset = null;
                OpenFileDialog openDlg = new OpenFileDialog();
                openDlg.ShowDialog();
                dataset     = Dataset.Read(openDlg.FileName);
                datasetName = openDlg.FileName;

                switch (cbFunction.SelectedItem.ToString())
                {
                case "Spectral Graph for GB-S3VDD":
                case "Spectral Graph":
                case "Clustering":
                    lstPoint       = dataset.Data.ToList();
                    graph          = new GraphBase(dataset, double.Parse(txtXichma.Text), int.Parse(txtK.Text));
                    graph.myCanvas = drawingPad;
                    graph.DrawDataset();
                    break;
                }
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }
        }