using (SqlCommand command = new SqlCommand(@"SELECT * FROM @table", connection))
            {
                command.Parameters.AddWithValue("@table", table_name);
                using (SqlDataReader reader = command.ExecuteReader())
                {
                    while (reader.Read())
                        ...
                }
            }

using (SqlCommand command = new SqlCommand(string.Format(@"SELECT * FROM {0}",table_name), connection))
            {
                using (SqlDataReader reader = command.ExecuteReader())
                {
                    while (reader.Read())
                        ...
                }
            }