封装sqlhelper类

using System;
using System.Collections.Generic;
using System.Data;
using System.Data.Common;
using System.Data.SqlClient;
using System.Linq;
using System.Web;

namespace WXCustomerCard.DataAccess {
    public class DataBase {
        private string connectionString ="server=.;uid=sa;password=123456;Database=WXCustomerCard;max pool size=1000";//server=120.24.159.211;uid=sa;password=20894796@qq.com;Database=WXCustomerCard;max pool size=1000

        //private string connectionString = "server=120.24.159.211;uid=sa;password=20894796@qq.com;Database=WXCustomerCard;max pool size=1000";//"server=.;uid=sa;password=123456;Database=WXCustomerCard;max pool size=1000";//server=120.24.159.211;uid=sa;password=20894796@qq.com;Database=WXCustomerCard;max pool size=1000
        public DataBase() {
        }
        public DataBase(string conStr) {
            connectionString = conStr;
        }

        public object ExecuteScalar(string sql,List< DbParameter> parameters = null) {
            try {
                using (SqlConnection connection = new SqlConnection(connectionString)) {
                    using (SqlCommand command = connection.CreateCommand()) {
                        command.CommandType = CommandType.Text;
                        command.CommandText = sql;
                        if (parameters != null && parameters.Count > 0) {
                            foreach (SqlParameter item in parameters) {
                                command.Parameters.Add(item);
                            }
                        }
                        connection.Open();
                        var data = command.ExecuteScalar();
                        command.Parameters.Clear();
                        return data;
                    }
                }
            }
            catch (Exception ex) {
                throw ex;
            }
        }
        public bool ExecuteNonQuery(string sql, List<DbParameter> parameters = null) {
            try {
                using (SqlConnection connection = new SqlConnection(connectionString)) {
                    using (SqlCommand command = connection.CreateCommand()) {
                        command.CommandType = CommandType.Text;
                        command.CommandText = sql;

                        if (parameters != null && parameters.Count > 0) {
                            foreach (SqlParameter item in parameters) {
                                command.Parameters.Add(item);
                            }
                        }
                        connection.Open();
                        return command.ExecuteNonQuery() > 0;
                    }
                }
            }
            catch (Exception ex) {
                throw ex;
            }
        }
        public List<T> ExecuteReader<T>(string sql, List<DbParameter> parameters = null) where T : class, new() {
            try {
                using (SqlConnection connection = new SqlConnection(connectionString)) {
                    using (SqlCommand command = connection.CreateCommand()) {
                        command.CommandType = CommandType.Text;
                        command.CommandText = sql;

                        if (parameters != null && parameters.Count > 0) {
                            foreach (SqlParameter item in parameters) {
                                command.Parameters.Add(item);
                            }
                        }

                        connection.Open();

                        T t = new T();

                        var task = command.ExecuteReader();
                        List<T> list = DataConvert.DataReaderToEntities<T>(task);
                        if (list != null && list.Count > 0) {
                            return list;
                        }
                        return null;
                    }
                }
            }
            catch (Exception ex) {
                throw ex;
            }
        }

    }
}