private void button2_Click(object sender, EventArgs e)
        {
            this.Hide();
            StockMain main = new StockMain();

            main.Show();
        }
        private void button2_Click(object sender, EventArgs e)
        {
            SqlConnection  con = new SqlConnection(@"Data Source=(LocalDb)\LocalDBDemo;Initial Catalog=Stock;Integrated Security=True");
            SqlDataAdapter sda = new SqlDataAdapter(@"SELECT *
  FROM[dbo].[Login] where Username = '******' and Password = '******'", con);
            DataTable      dt  = new DataTable();

            sda.Fill(dt);
            if (dt.Rows.Count == 1)
            {
                this.Hide();
                StockMain main = new StockMain();
                main.Show();
            }
            else
            {
                MessageBox.Show("Invalid Username or Password !", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
                button1_Click(sender, e);
            }
        }