public partial class Form1 : Form
    {
        List<A> list = new List<A>();
        BindingSource bs = new BindingSource();
        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Shown(object sender, EventArgs e)
        {
            list.Add(new A() { Id = 1, Name = "Name1" });
            list.Add(new A() { Id = 2, Name = "Name2" });
            list.Add(new A() { Id = 3, Name = "Name3" });
            list.Add(new A() { Id = 4, Name = "Name4" });

            bs.DataSource = list;

            dataGridView1.DataSource = bs;

            textBox1.DataBindings.Add("Text", bs, "Name");

            bs.CurrentItemChanged += bs_CurrentItemChanged;
        }

        void bs_CurrentItemChanged(object sender, EventArgs e)
        {
            A item = bs.Current as A;
            textBox2.Text = item.ToString();
        }
    }

    public class A : INotifyPropertyChanged
    {
        private int id;
        private string name;

        public int Id
        {
            get
            {
                return id;
            }
            set
            {
                id = value;
                PropertyChangedFun("Id");
            }
        }

        public string Name
        {
            get
            {
                return name;
            }
            set
            {
                name = value;
                PropertyChangedFun("Name");
            }
        }


        public event PropertyChangedEventHandler PropertyChanged;
        void PropertyChangedFun(string propName)
        {
            if (PropertyChanged != null)
                PropertyChanged(this, new PropertyChangedEventArgs(propName));
        }

        public override string ToString()
        {
            return string.Format("{0}:{1}",id, name);
        }
    }