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  • 常用DBHelper类

     public class DBHelper
        {
            SqlConnection conn = null;

            public DBHelper()
            {
                 string str = ConfigurationManager.ConnectionStrings["sql"].ConnectionString;
                 conn = new SqlConnection(str);
            }

            /// 创建执行sql语句命令方法
            /// <summary>
            /// 创建执行sql语句命令方法
            /// </summary>
            /// <param name="sql">sql语句</param>
            /// <param name="param">参数集合</param>
            /// <returns>返回cmd命令</returns>
            protected SqlCommand CreateCommand(string sql, SqlParameter[] param)
            {
                SqlCommand cmd = new SqlCommand(sql, conn);
                if (param != null)
                {
                    cmd.Parameters.AddRange(param);
                }
                return cmd;
            }

            /// 创建储存过程命令方法
            /// <summary>
            /// 创建储存过程命令方法
            /// </summary>
            /// <param name="procName">储存过程名字</param>
            /// <param name="param">参数集合</param>
            /// <returns>返回cmd命令</returns>
            protected SqlCommand CreateProcCommand(string procName, SqlParameter[] param)
            {
                SqlCommand cmd = new SqlCommand(procName, conn);
                cmd.CommandType = CommandType.StoredProcedure;
                if (param != null)
                {
                    cmd.Parameters.AddRange(param);
                }
                return cmd;
            }

            /// 执行增删改command命令
            /// <summary>
            /// 执行增删改command命令
            /// </summary>
            /// <param name="cmd">cmd命令</param>
            /// <returns>返回受影响行数</returns>
            protected int ExecuteCommand(SqlCommand cmd)
            {
                int i = 0;
                cmd.Connection.Open();
                i = cmd.ExecuteNonQuery();
                cmd.Connection.Close();
                return i;
            }

            /// 创建查看command命令
            /// <summary>
            /// 创建查看command命令
            /// </summary>
            /// <param name="cmd">cmd命令</param>
            /// <returns>返回读取命令</returns>
            protected SqlDataReader ExecuteReaderCommand(SqlCommand cmd)
            {

                cmd.Connection.Open();
                SqlDataReader dr = cmd.ExecuteReader(CommandBehavior.CloseConnection);
                return dr;
            }

            /// 创建查询Command命令
            /// <summary>
            /// 创建查询Command命令
            /// </summary>
            /// <param name="cmd">cmd命令</param>
            /// <returns>返回查询内容</returns>
            protected object ExecuteScalarCommand(SqlCommand cmd)
            {
                object i = 0;
                cmd.Connection.Open();
                i = cmd.ExecuteScalar();
                cmd.Connection.Close();
                return i;
            }

            /// 创建参数方法
            /// <summary>
            /// 创建参数方法
            /// </summary>
            /// <param name="paramName">参数名字</param>
            /// <param name="type">参数类型</param>
            /// <param name="length">类型长度</param>
            /// <param name="value">参数值</param>
            /// <returns>返回参数</returns>
            protected SqlParameter CreateInputParam(string paramName, SqlDbType type, int length, object value)
            {
                SqlParameter param = new SqlParameter(paramName, type, length);
                param.Value = value;
                return param;
            }

        }

    /////调用事例:

            /// 分页查询收藏夹

            /// <summary>
            /// 分页查询收藏夹
            /// </summary>
            /// <param name="name">用户名</param>
            /// <param name="pageindex">当前页下标</param>
            /// <param name="pagesize">每页显示数量</param>
            /// <returns>商品集合</returns>
            public List<CollectInfoModel> GetGroupCollectByUserName(string name,int pageindex,int pagesize)
            {
                List<CollectInfoModel> list = new List<CollectInfoModel>();
                string sql = "select top(@size) * from CollectInfo where cid not in (select top(@size*(@index-1)) cid from CollectInfo) and name=@name";
                SqlParameter[] pram = new SqlParameter[]
                {
                    new SqlParameter("@name",name),
                    new SqlParameter("@size",pagesize),
                    new SqlParameter("@index",pageindex)
                };
                SqlDataReader dr = ExecuteReaderCommand(CreateCommand(sql, pram));
                while (dr.Read())
                {
                    CollectInfoModel c = new CollectInfoModel();
                    c.Cid = (int)dr["cid"];
                    c.CPid = new ProductInfoModel();
                    ProductInfoService pser = new ProductInfoService();
                    c.CPid = pser.SelectProductById(Convert.ToInt32(dr["cPid"]));
                    c.Name = (string)dr["name"];
                    c.Time = (DateTime)dr["time"];
                    list.Add(c);
                }
                dr.Close();
                return list;
            }

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  • 原文地址:https://www.cnblogs.com/shinggang/p/2001320.html
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