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.Xml;

namespace datagrid
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }
        DataTable DTable;
        BindingSource SBind; //zmienne globalne 

        private void button1_Click(object sender, EventArgs e)
        {
            DTable = new DataTable(); //nowa tebelka danych
            SBind = new BindingSource(); //obiekt 'komunikatora' miedzy DataTable a DataGridView
            SBind.DataSource = DTable; // 1st lvl connection
            dataGridView1.DataSource = SBind; // final connection

            //teraz możemy robić co chcemy z DataTable, a dataGridView będzie automatycznie aktualizowal swój stan
            DTable.Clear();
            DTable.Columns.Add("Name");
            DTable.Columns.Add("Marks");
            DataRow row = DTable.NewRow();
            row["Name"] = "pierwszy";
            row["Marks"] = "500";
            DTable.Rows.Add(row); 
        }

        private void button2_Click(object sender, EventArgs e)
        {
            DTable.TableName = "Tablica danych";  //bez tego linijka niżej wyrzuci błąd!
            DTable.WriteXml("dane.xml");
        }

        private void button3_Click(object sender, EventArgs e)
        {
            dataGridView1.DataSource = null;
            dataGridView1.AutoGenerateColumns = true;
            XmlReader xmlFile = XmlReader.Create("dane.xml", new XmlReaderSettings());
            DataSet data = new DataSet();
            data.ReadXml(xmlFile);
            xmlFile.Close();

            DTable = data.Tables[0];
            SBind = new BindingSource();
            SBind.DataSource = DTable;
            dataGridView1.DataSource = SBind;
        }
    }
}