C reads the data in the CSV file and displays it after importing the DataTable

1    99    99    99
2    88    88    88
3    77    77    77
4    66    66    66
5    55    55    55
6    44    44    44
7    33    33    33
8    22    22    22
9    11    11    11
10    0    0    0

private void button4_Click(object sender, EventArgs e)
        {
            string fileName = string.Empty;
            string strFilePath = System.IO.Directory.GetCurrentDirectory();


            OpenFileDialog openFileDialog = new OpenFileDialog();
            openFileDialog.InitialDirectory = strFilePath;
            openFileDialog.Filter = "(*.CSV)|*.CSV";
            openFileDialog.Title = " Open data file ";
            DialogResult result = openFileDialog.ShowDialog();

            if (result != DialogResult.OK)
                return;
            List<string> listA=new List<string>();
            List<string> listB = new List<string>();
            List<string> listC = new List<string>();

            fileName = openFileDialog.FileName;
            using (var reader = new StreamReader(fileName))
            {
                while (!reader.EndOfStream)
                { 
                    var line= reader.ReadLine();
                    var values= line.Split('\t');
                    if (values.Length != 3)
                    {
                        MessageBox.Show(
                            " Not a legal data source , The program failed to import data ~！",
                            " Prompt information ",
                            MessageBoxButtons.OK,
                            MessageBoxIcon.Warning
                            );
                        return;
                    }
                    listA.Add(values[0]);
                    listB.Add(values[1]);
                    listC.Add(values[2]);
                }
            }
            
            string[,] data = new string[listA.Count,3];
            for (int i = 0; i < listA.Count; i++)
            { 
                data[i,0] = listA[i];
                data[i, 1] = listB[i];
                data[i, 2] = listC[i];
                Console.WriteLine($"{data[i, 0]} {data[i, 1]} {data[i, 2]}");
            }
            // Two dimensional array   turn  DataTable  data source 
            DataTable dt = new DataTable();
            for (int i = 0; i < data.GetLength(1); i++)
                dt.Columns.Add(i.ToString(), typeof(int));

            for (int i = 0; i < data.GetLength(0); i++)
            {
                DataRow dr = dt.NewRow();
                for (int j = 0; j < data.GetLength(1); j++)
                    dr[j] = data[i, j];
                dt.Rows.Add(dr);
            }
            dataGridView1.DataSource = dt;
        }