三层架构保存，更新，查询等一些列方法

业务逻辑层的方法

  public class AdminManager
    {
        public static List<Admin> GetAdminByNameAndPhone(string name,string phone)
        {
            return AdminService.GetAdminByNameAndPhone(name,phone);
        }


        public static int UpdateAdmin(Admin admin)
        {
            return AdminService.UpdateAdmin(admin);
        }
        public static int DeleteAdmin(int id)
        {
            return AdminService.DeleteAdminById(id);
        }

        public static List<Admin> GetAllAdmin()
        {
            return AdminService.GetAllAdmin();
        }
        public static Admin GetAdminById(int id)
        {
            return AdminService.GetAdmin(id);
        }

        #region 添加管理员
        /// <summary>
        /// 添加管理员
        /// </summary>
        /// <param name="admin">管理员对象</param>
        /// <returns>添加之后此管理员的编号</returns>
        public static int AddAdmin(Admin admin)
        {
            //判断是否存在
            if (AdminService.GetAdminByLoginId(admin.LoginId) > 0)
            {
                return 0;   //存在
            }
            return AdminService.AddAdmin(admin);
        }
        #endregion

        #region 管理员登陆
        /// <summary>
        /// 管理员登录
        /// </summary>
        /// <param name="admin">管理员对象</param>
        /// <returns>登录状态</returns>
        public static bool Login(ref Admin admin)
        {
            admin = AdminService.GetAdminByParas(admin);
            if (admin.Id != 0)
            {
                return true;
            }
            return false;
        }
        #endregion

        #region 根据登陆名查询管理员
        /// <summary>
        /// 根据登陆名查询管理员
        /// </summary>
        /// <param name="loginId">登陆名</param>
        /// <returns>符合条件的管理员个数</returns>
        public static bool GetAdminByLoginId(string loginId)
        {
            int count = AdminService.GetAdminByLoginId(loginId);
            if (count > 0)
                return true;
            return false;
        }
        #endregion 


    }

数据访问层

   public class AdminService
    {
        private const string INSERT = "INSERT INTO Admin VALUES (@LoginId,@LoginPwd,@Name,@Phone);SELECT @@IDENTITY";
        private const string UPDATE = "UPDATE Admin SET LoginId=@LoginId,LoginPwd=@LoginPwd,Name=@Name,Phone=@Phone WHERE Id=@Id";
        private const string DELETE_BY_ID = "DELETE FROM Admin WHERE Id=@Id";
        private const string SELECT_ALL = "SELECT * FROM Admin";
        private const string SELECT_BY_ID = "SELECT * FROM Admin WHERE Id=@Id";
        private const string SELECT_BY_LOGIN = "SELECT * FROM Admin WHERE LoginId=@LoginId and LoginPwd=@LoginPwd";
        private const string SELECT_COUNT_BY_LOGINID = "SELECT COUNT(*) FROM Admin WHERE LoginId=@LoginId";

        #region 
        public static List<Admin> GetAdminByNameAndPhone(string name,string phone)
        {
            //proc_GetAdminByNamePhone
            SqlParameter[] pars = new SqlParameter[]{
                new SqlParameter("@name",name),
                new SqlParameter("@phone",phone)
            };

            return GetAdminBySql(CommandType.StoredProcedure, "proc_GetAdminByNamePhone", pars);
        }
        #endregion


        public static int AddAdmin(Admin admin)
        {
            SqlParameter[] paras = new SqlParameter[]{
                new SqlParameter("@LoginId", admin.LoginId),
                new SqlParameter("@LoginPwd", admin.LoginPwd),
                new SqlParameter("@Name", admin.Name),
                new SqlParameter("@Phone", admin.Phone)
            };
            int id = Convert.ToInt32(DBHelper.ExecuteScalar(CommandType.Text, INSERT, paras));
            return id;
        }
        public static int UpdateAdmin(Admin admin)
        {
            SqlParameter[] paras = new SqlParameter[]{
                new SqlParameter("@Id", admin.Id),
                new SqlParameter("@LoginId", admin.LoginId),
                new SqlParameter("@LoginPwd", admin.LoginPwd),
                new SqlParameter("@Name", admin.Name),
                new SqlParameter("@Phone", admin.Phone)
            };
            int rowCount = Convert.ToInt32(DBHelper.ExecuteNonQuery(CommandType.Text, UPDATE, paras));
            return rowCount;
        }
        public static int DeleteAdminById(int id)
        {
            SqlParameter para = new SqlParameter("@Id", id);
            int rowCount = Convert.ToInt32(DBHelper.ExecuteNonQuery(CommandType.Text, DELETE_BY_ID, para));
            return rowCount;
        }
        public static Admin GetAdmin(int id)
        {
            SqlParameter paras = new SqlParameter("@Id", id);
            List<Admin> list = GetAdminBySql(CommandType.Text, SELECT_BY_ID, paras);
            if (list.Count > 0)
            {
                return list[0];
            }
            return new Admin();
        }
        public static List<Admin> GetAllAdmin()
        {
            return GetAdminBySql(CommandType.Text, SELECT_ALL, null);
        }
        
        //查询语句中字段为 * 时的通用方法。
        private static List<Admin> GetAdminBySql(CommandType commandType, string commandText, params SqlParameter[] paras)
        {
            List<Admin> list = new List<Admin>();
            using (SqlDataReader reader = DBHelper.ExecuteGetReader(commandType, commandText, paras))
            {
                while (reader.Read())
                {
                    Admin admin = new Admin
                    {
                        Id = (int)reader["Id"],
                        LoginId = reader["LoginId"].ToString(),
                        LoginPwd = reader["LoginPwd"].ToString(),
                        Name = reader["Name"].ToString(),
                        Phone = reader["Phone"].ToString()
                    };
                    list.Add(admin);
                }
            }
            return list;
        }

        #region 根据登录名和密码查询管理员
        /// <summary>
        /// 根据登录名和密码查询管理员
        /// </summary>
        /// <param name="admin">用户对象</param>
        /// <returns>用户对象</returns>
        public static Admin GetAdminByParas(Admin admin)
        {
            SqlParameter[] paras = new SqlParameter[] { 
                new SqlParameter("@LoginId",admin.LoginId),
                new SqlParameter("@LoginPwd",admin.LoginPwd)
            };
            List<Admin> adminList = GetAdminBySql(CommandType.Text, SELECT_BY_LOGIN, paras);
            if (adminList.Count > 0)
                return adminList[0];
            else
                return admin;
        }
        #endregion
        #region 根据登陆名查询管理员
        /// <summary>
        /// 根据登陆名查询管理员
        /// </summary>
        /// <param name="loginId">登陆名</param>
        /// <returns>符合条件的管理员个数</returns>
        public static int GetAdminByLoginId(string loginId)
        {
            SqlParameter para = new SqlParameter("@LoginId", loginId);
            return Convert.ToInt32(DBHelper.ExecuteScalar(CommandType.Text, SELECT_COUNT_BY_LOGINID, para));
        }
        #endregion  

    }

dephlpe

   /// <summary>
    /// 执行Sql 命令的通用方法
    /// </summary>
    public abstract class SqlHelper
    {

        //Database connection strings
        public static string ConnectionString = "Data Source=.;Initial Catalog=PB_BookShopDemo;Integrated Security=True";

        #region ExecuteNonQuery
        /// <summary>
        /// 执行sql命令
        /// </summary>
        /// <param name="connectionString"></param>
        /// <param name="commandType"></param>
        /// <param name="commandText">sql语句/参数化sql语句/存储过程名</param>
        /// <param name="commandParameters"></param>
        /// <returns>受影响的行数</returns>
        public static int ExecuteNonQuery(string connectionString, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
        {

            SqlCommand cmd = new SqlCommand();

            using (SqlConnection conn = new SqlConnection(connectionString))
            {
                PrepareCommand(cmd, commandType,conn, commandText, commandParameters);
                int val = cmd.ExecuteNonQuery();

                return val;
            }
        }

        /// <summary>
        /// 执行Sql Server存储过程
        /// </summary>
        /// <param name="connectionString"></param>
        /// <param name="spName">存储过程名</param>
        /// <param name="parameterValues"></param>
        /// <returns>受影响的行数</returns>
        public static int ExecuteNonQuery(string connectionString, string spName, params object[] parameterValues)
        {

            using (SqlConnection conn = new SqlConnection(connectionString))
            {
                SqlCommand cmd = new SqlCommand();

                PrepareCommand(cmd, conn, spName, parameterValues);
                int val = cmd.ExecuteNonQuery();

                return val;
            }
        }
        #endregion

        #region ExecuteReader
        /// <summary>
        ///  执行sql命令
        /// </summary>
        /// <param name="connectionString"></param>
        /// <param name="commandType"></param>
        /// <param name="commandText"></param>
        /// <param name="commandParameters"></param>
        /// <returns>SqlDataReader 对象</returns>
        public static SqlDataReader ExecuteReader(string connectionString, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
        {

            SqlConnection conn = new SqlConnection(connectionString);
            try
            {
                SqlCommand cmd = new SqlCommand();
                PrepareCommand(cmd, commandType, conn, commandText, commandParameters);
                SqlDataReader rdr = cmd.ExecuteReader(CommandBehavior.CloseConnection);

                return rdr;
            }
            catch
            {
                conn.Close();
                throw;
            }
        }

        public static SqlDataReader ExecuteReader(string connectionString, string spName, params object[] parameterValues)
        {
            SqlConnection conn = new SqlConnection(connectionString);
            try
            {
                SqlCommand cmd = new SqlCommand();

                PrepareCommand(cmd, conn, spName, parameterValues);
                SqlDataReader rdr = cmd.ExecuteReader(CommandBehavior.CloseConnection);

                return rdr;
            }
            catch
            {
                conn.Close();
                throw;
            }

        }
        #endregion

        #region ExecuteDataset


        public static DataSet ExecuteDataset(string connectionString, string spName, params object[] parameterValues)
        {
            using (SqlConnection conn = new SqlConnection(connectionString))
            {
                SqlCommand cmd = new SqlCommand();

                PrepareCommand(cmd, conn, spName, parameterValues);

                using (SqlDataAdapter da = new SqlDataAdapter(cmd))
                {
                    DataSet ds = new DataSet();

                    da.Fill(ds);

                    return ds;
                }
            }
        }


        public static DataSet ExecuteDataset(string connectionString, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
        {
            using (SqlConnection conn = new SqlConnection(connectionString))
            {

                SqlCommand cmd = new SqlCommand();

                PrepareCommand(cmd, commandType, conn, commandText, commandParameters);
                using (SqlDataAdapter da = new SqlDataAdapter(cmd))
                {
                    DataSet ds = new DataSet();

                    da.Fill(ds);

                    return ds;
                }
            }
        }

        #endregion

        #region ExecuteScalar
        /// <summary>
        /// 执行Sql 语句
        /// </summary>
        /// <param name="connectionString">连接字符串</param>
        /// <param name="spName">Sql 语句/参数化的sql语句</param>
        /// <param name="parameterValues">参数</param>
        /// <returns>执行结果对象</returns>
        public static object ExecuteScalar(string connectionString, CommandType commandType, string commandText, params SqlParameter[] commandParameters)
        {
            SqlCommand cmd = new SqlCommand();

            using (SqlConnection conn = new SqlConnection(connectionString))
            {
                PrepareCommand(cmd, commandType, conn, commandText, commandParameters);
                object val = cmd.ExecuteScalar();

                return val;
            }
        }

        /// <summary>
        /// 执行存储过程
        /// </summary>
        /// <param name="connectionString">连接字符串</param>
        /// <param name="spName">存储过程名</param>
        /// <param name="parameterValues">存储过程参数</param>
        /// <returns>执行结果对象</returns>
        public static object ExecuteScalar(string connectionString, string spName, params object[] parameterValues)
        {
            SqlCommand cmd = new SqlCommand();

            using (SqlConnection conn = new SqlConnection(connectionString))
            {
                PrepareCommand(cmd, conn, spName, parameterValues);
                object val = cmd.ExecuteScalar();

                return val;
            }
        }


        #endregion

        #region Private Method
        /// <summary>
        /// 设置一个等待执行的SqlCommand对象
        /// </summary>
        /// <param name="cmd">SqlCommand 对象，不允许空对象</param>
        /// <param name="conn">SqlConnection 对象，不允许空对象</param>
        /// <param name="commandText">Sql 语句</param>
        /// <param name="cmdParms">SqlParameters  对象,允许为空对象</param>
        private static void PrepareCommand(SqlCommand cmd, CommandType commandType, SqlConnection conn, string commandText, SqlParameter[] cmdParms)
        {
            //打开连接
            if (conn.State != ConnectionState.Open)
                conn.Open();

            //设置SqlCommand对象
            cmd.Connection = conn;
            cmd.CommandText = commandText;
            cmd.CommandType = commandType;

            if (cmdParms != null)
            {
                foreach (SqlParameter parm in cmdParms)
                    cmd.Parameters.Add(parm);
            }
        }

        /// <summary>
        /// 设置一个等待执行存储过程的SqlCommand对象
        /// </summary>
        /// <param name="cmd">SqlCommand 对象，不允许空对象</param>
        /// <param name="conn">SqlConnection 对象，不允许空对象</param>
        /// <param name="spName">Sql 语句</param>
        /// <param name="parameterValues">不定个数的存储过程参数，允许为空</param>
        private static void PrepareCommand(SqlCommand cmd, SqlConnection conn, string spName, params object[] parameterValues)
        {
            //打开连接
            if (conn.State != ConnectionState.Open)
                conn.Open();

            //设置SqlCommand对象
            cmd.Connection = conn;
            cmd.CommandText = spName;
            cmd.CommandType = CommandType.StoredProcedure;

            //获取存储过程的参数
            SqlCommandBuilder.DeriveParameters(cmd);

            //移除Return_Value 参数
            cmd.Parameters.RemoveAt(0);

            //设置参数值
            if (parameterValues != null)
            {
                for (int i = 0; i < cmd.Parameters.Count; i++)
                {
                    cmd.Parameters[i].Value = parameterValues[i];

                }
            }
        }
        #endregion


    }