private static readonly string str = ConfigurationManager.ConnectionStrings["strCon"].ConnectionString;

        public static DataTable GetTable(string sql)

        {

            DataTable dt = new DataTable();

            using (SqlDataAdapter sda = new SqlDataAdapter(sql, str))

            {

                sda.Fill(dt);

            }

            return dt;

        }

        public static int ExecuteNonQuery(string sql, params SqlParameter[] param)

        {

            using (SqlConnection con = new SqlConnection(str))

            {

                using (SqlCommand cmd = new SqlCommand(sql, con))

                {

                    cmd.Parameters.AddRange (param);

                    con.Open();

                    return cmd.ExecuteNonQuery();

                }

            }

        }

        public static object ExecuteScalar(string sql, params SqlParameter[] param)

        {

            using (SqlConnection con = new SqlConnection(str))

            {

                using (SqlCommand cmd = new SqlCommand(sql, con))

                {

                    cmd.Parameters.AddRange  (param);

                    con.Open();

                    return cmd.ExecuteScalar();

                }

            }

        }

        public static SqlDataReader ExecuteReader(string sql, params SqlParameter[] param)

        {

            SqlConnection con = new SqlConnection(str);

            using (SqlCommand cmd = new SqlCommand(sql, con))

            {

                cmd.Parameters.AddRange(param);

                try

                {

                    con.Open();

                    return cmd.ExecuteReader(System.Data.CommandBehavior.CloseConnection);

                }

                catch (Exception ex)

                {

                    throw ex;

                }

            }

        }