public partial class Form2 : Form
    {
        private SqlConnection con = null;
        private SqlCommand cmd = null;
        private SqlDataReader dr = null;
        private List<UserInfo> listUser = null;
        public Form2()
        {
            InitializeComponent();
        }

        private void Form2_Load(object sender, EventArgs e)
        {
            using (con = new SqlConnection("Data Source=.;DataBase=TEST;Uid=sa;Pwd=123456;"))
            {
                using (cmd = new SqlCommand())
                {
                    cmd.CommandText = "select * from dbo.UserInfo_tb";
                    cmd.Connection = con;
                    try
                    {
                        if (con.State == ConnectionState.Closed)
                        {
                            con.Open();
                        }
                        listUser = new List<UserInfo>();
                        dr = cmd.ExecuteReader();
                        while (dr.Read())
                        {
                            UserInfo user = new UserInfo { UserID = dr.GetString(0), UserName = dr.GetString(1), Eamil = dr.GetString(2), Telephone = dr.GetString(3) };
                            listUser.Add(user);
                        }
                        dataGridView1.DataSource = listUser;
                    }
                    catch (DataException ex)
                    {
                        MessageBox.Show(ex.Message, "错误信息", MessageBoxButtons.OK, MessageBoxIcon.Error);
                    }
                    finally
                    {
                        if (con.State == ConnectionState.Open)
                        {
                            con.Close();
                        }
                    }
                }
            }
        }
    }
    public class UserInfo
    {
        public string UserID { get; set; }
        public string UserName { get; set; }
        public string Eamil { get; set; }
        public string Telephone { get; set; }
    }