
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

using System.IO;
using System.Windows.Forms.DataVisualization.Charting;

namespace Table
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
            tabControl.TabPages.Clear();
        }

        private void openMenuItem_Click(object sender, EventArgs e)
        {
            if (openDialog.ShowDialog() == DialogResult.OK)
            {
                string fileName = openDialog.FileName;

                TabPage page = new TabPage();
                tabControl.TabPages.Add(page);
                tabControl.SelectedTab = page;

                FileInfo info = new FileInfo(fileName);
                page.Text = info.Name;
                page.Name = info.FullName;

                DataGridView grid = new DataGridView();
                page.Controls.Add(grid);
                grid.Dock = DockStyle.Fill;

                string[] lines = File.ReadAllLines(fileName);
                int columns = 0;
                List data = new List();
                foreach (string line in lines)
                {
                    string[] items = line.Split(',');
                    if (items.Length > columns)
                        columns = items.Length;
                    if (items.Length > 0)
                        if (items.Length > 1 || items[0] != "")
                            data.Add(items);
                }

                for (int i = 1; i <= columns; i++)
                    grid.Columns.Add("column" + i, "column " + i);

                Text = "" + data.Count;
                foreach (string[] items in data)
                    grid.Rows.Add(items);
            }
        }

        private void saveMenuItem_Click(object sender, EventArgs e)
        {
            TabPage page = tabControl.SelectedTab;
            if (page != null)
            {
                Control control = page.Controls[0];
                if (control is DataGridView)
                {
                    DataGridView grid = control as DataGridView;
                    if (saveDialog.ShowDialog() == DialogResult.OK)
                    {
                        string fileName = openDialog.FileName;
                        List  lines = new List ();
                        foreach (DataGridViewRow r in grid.Rows)
                        {
                            string line = "";
                            int cnt = 0;
                            foreach (DataGridViewCell c in r.Cells)
                            {
                                string item = "";
                                if (c.Value != null)
                                   item = c.Value.ToString ();
                                if (cnt > 0) line = line + ",";
                                line = line + item;
                                cnt ++;
                            }
                            lines.Add(line);
                        }
                        File.WriteAllLines(fileName, lines.ToArray ());
                    }
                }
            }
        }

        private void chartMenuItem_Click(object sender, EventArgs e)
        {
            if (openDialog.ShowDialog() == DialogResult.OK)
            {
                string fileName = openDialog.FileName;

                TabPage page = new TabPage();
                tabControl.TabPages.Add(page);
                tabControl.SelectedTab = page;

                FileInfo info = new FileInfo(fileName);
                page.Text = info.Name;
                page.Name = info.FullName;

                // using System.Windows.Forms.DataVisualization.Charting;
                Chart chart = new Chart();
                page.Controls.Add (chart);
                chart.Dock = DockStyle.Fill;

                chart.Size = new Size(300, 300);

                ChartArea chartArea = new ChartArea();
                chartArea.Name = "ChartArea";
                chart.ChartAreas.Add (chartArea);

                chart.Series.Clear();
                Series data = chart.Series.Add("");
                data.ChartType = SeriesChartType.Pie;

                string[] lines = File.ReadAllLines(fileName);
                foreach (string line in lines)
                {
                    string[] items = line.Split(',');
                    int cnt = items.Length;
                    string value = (cnt >= 1) ? items[0] : "";
                    string name = (cnt >= 2) ? items[1] : "";

                    int number = 0;
                    int.TryParse(value, out number);

                    data.Points.AddXY(name, number);
                }
            }

        }
        private void quitMenuItem_Click(object sender, EventArgs e)
        {
            Close();
        }

    }
}

abc.txt


1, 2, 3
10, 20, 30
100, 200, 300

debian.csv


4,Etch
5,Lenny
6,Squeeze
7,Wheezy
8,Jessie
9,Stretch
10,Buster
11,Bullseye
12,Bookworm

[[http://kmlinux.fjfi.cvut.cz/~culikzde/pw/2021/Table2021.zip|zip]]