public partial class Form1 : Form
    {
        BindingSource bs;
        DataClasses1DataContext db;

        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {            
            bs.DataSource = db.Roles;            
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            db = new DataClasses1DataContext();
            bs = new BindingSource();
            bs.DataSource = db.Roles;
            this.dataGridView1.DataSource = bs;
        }
    }