using System.Data.SqlClient;

static void Main(string[] args)
        {
            string connString = @"Data Source=.; Initial Catalog=lh0216; User ID=sa;pwd=Founder123";
            //出了using括号objConnection类会被自动释放
            using (SqlConnection objConnection = new SqlConnection(connString))
            {
                objConnection.Open();
                Console.WriteLine("数据库连接成功。");               
            }            
            Console.ReadKey();
        }