.Net平台下的SqlHelper

class SqlHelper
    {
        //通过ConfigurationManager可以读到App.config中的配置信息
        private static string conStr = ConfigurationManager.ConnectionStrings["dbConStr"].ConnectionString;

        /// <summary>
        /// 将null转换成数据库中的DBNull
        /// </summary>
        /// <param name="value"></param>
        /// <returns></returns>
        public static object ToDBValue(object value)
        {
            if (value == null)
                value = DBNull.Value;
            return value;
        }

        /// <summary>
        /// 从数据库中获得DBNull数据转换成null
        /// </summary>
        /// <param name="value"></param>
        /// <returns></returns>
        public static object FromDBValue(object value)
        {
            if (value == DBNull.Value)
                value = null;
            return value;
        }

        /// <summary>
        /// 执行不查询sql语句
        /// </summary>
        /// <param name="sql">要执行的sql语句</param>
        /// <returns>执行完sql语句后，数据库受影响的行数</returns>
        public static int ExecuteNonQuery(string sql,params SqlParameter[] parameters)
        {
            using (SqlConnection sqlCon = new SqlConnection(conStr))
            {
                sqlCon.Open();
                using (SqlCommand sqlCmd = sqlCon.CreateCommand())
                {
                    sqlCmd.CommandText = sql;
                    //foreach (SqlParameter param in parameters)
                    //{
                    //    sqlCmd.Parameters.Add(param);
                    //}
                    sqlCmd.Parameters.AddRange(parameters);
                    return sqlCmd.ExecuteNonQuery();
                }
            }
        }

        /// <summary>
        /// 执行查询
        /// </summary>
        /// <param name="sql">要执行的sql语句</param>
        /// <returns>返回查询结果中的第一行第一列</returns>
        public static object ExecuteScaler(string sql,params SqlParameter[] parameters)
        {
            using (SqlConnection sqlCon = new SqlConnection(conStr))
            {
                sqlCon.Open();
                using (SqlCommand sqlCmd = sqlCon.CreateCommand())
                {
                    sqlCmd.CommandText = sql;
                    sqlCmd.Parameters.AddRange(parameters);
                    return sqlCmd.ExecuteScalar();
                }
            }
        }

        /// <summary>
        /// 执行离线数据集查询
        /// </summary>
        /// <param name="sql">要执行的sql语句</param>
        /// <returns>返回离线数据集</returns>
        public static DataTable ExecuteDataTable(string sql,params SqlParameter[] parameters)
        {
            using (SqlConnection sqlCon = new SqlConnection(conStr))
            {
                sqlCon.Open();
                using (SqlCommand sqlCmd = sqlCon.CreateCommand())
                {
                    sqlCmd.CommandText = sql;
                    sqlCmd.Parameters.AddRange(parameters);
                    SqlDataAdapter sqlAdapter = new SqlDataAdapter(sqlCmd);
                    DataSet dataSet = new DataSet();
                    sqlAdapter.Fill(dataSet);
                    return dataSet.Tables[0];
                }
            }
        }

        /// <summary>
        /// 执行存储过程
        /// </summary>
        /// <param name="storedProc"></param>
        /// <param name="parameters"></param>
        /// <returns></returns>
        public static int ExecuteStoredProc(string storedProc,params SqlParameter[] parameters)
        {
            using (SqlConnection conn = new SqlConnection(conStr))
            {
                using (SqlCommand sqlCmd = new SqlCommand(storedProc, conn))
                {
                    //sql命令为存储过程
                    sqlCmd.CommandType = CommandType.StoredProcedure;
                    //添加参数
                    sqlCmd.Parameters.AddRange(parameters);
                    //晚打开，早关闭
                    conn.Open();
                    return sqlCmd.ExecuteNonQuery();
                }
            }

        }
    }