这个类是真正的数据库操作类，上面的那个类只是调用了这个封装类的方法进行的操作

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Linq.Expressions;
using System.Data.Entity;
using System.Data.Linq;
using System.Data.Objects;
using System.Reflection;
using System.Threading;
using System.Data;
using System.Data.Objects.DataClasses;
using JFrame.Utility;

namespace JFrame.AccessCommon
{
    public class DataCommon
    {
        static readonly string Connection = "name=EntitiesContainer";
        static readonly string ContainerName = "EntitiesContainer";
        ObjectContext entities;
        public DataCommon(string Connection, string ContainerName = "EntitiesContainer")
        {
            entities = new ObjectContext(Connection);
            entities.DefaultContainerName = ContainerName;
        }

        //POMonitorDBEntities entities = new ENTITY.POMonitorDBEntities(Connection);

        #region 根据SQL语句查询数据
        public IEnumerable<T> ExecuteQuery<T>(string conn, string query, params object[] parms)
        {
            try
            {
                if (string.IsNullOrEmpty(conn))
                {
                    return entities.ExecuteStoreQuery<T>(query, parms);
                }
                else
                {
                    DataContext myDC = new DataContext(conn);
                    return myDC.ExecuteQuery<T>(query, parms);
                }
            }
            catch (Exception ex)
            {
                throw new Exception(ex.Message);
            }
        }
        public IEnumerable<T> ExecuteQuery<T>(string query)
        {
            return ExecuteQuery<T>(string.Empty, query, new object[] { });
        }
        #endregion

        #region 执行操作类型SQl语句
        /// <summary>
        /// 执行SQL命令
        /// </summary>
        /// <param name="sqlCommand"></param>
        /// <returns></returns>
        public int ExecuteSqlCommand(string sqlCommand, string connection = null)
        {
            if (string.IsNullOrEmpty(connection))
                return entities.ExecuteStoreCommand(sqlCommand); //ExecuteCommand(sqlCommand);
            else
            {
                ObjectContext entitiesNew = new ObjectContext(connection);
                return entitiesNew.ExecuteStoreCommand(sqlCommand);
            }
        }
        /// <summary>
        /// 执行SQL命令
        /// </summary>
        /// <param name="sqlCommand"></param>
        /// <returns></returns>
        public void ExecuteSqlCommand(string sqlCommand)
        {
            ExecuteSqlCommand(connection: string.Empty, sqlCommand: sqlCommand);
        }
        #endregion


        #region 私有方法
        private ObjectSet<T> GetTable<T>() where T : class
        {
            try
            {
                ObjectSet<T> customers = entities.CreateObjectSet<T>();
                return customers;
            }
            catch (Exception ex)
            {
                throw ex;
            }

        }
        #endregion

        #region 统计指定条件的数据量
        /// <summary>
        /// 统计指定条件的数据量
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="query"></param>
        /// <returns></returns>
        public virtual int Count<T>(Expression<Func<T, bool>> query) where T : class
        {
            var table = GetTable<T>();
            return (from t in table
                    select t).Where(query).Count();
        }
        #endregion


        #region 获取单个实体
        /// <summary>
        /// 获取单个实体
        /// </summary>
        /// <typeparam name="T">泛型类型参数</typeparam>
        /// <param name="express">查询条件</param>
        /// <returns></returns>
        public virtual T GetSingleEntity<T>(Expression<Func<T, bool>> query) where T : class
        {
            try
            {
                var table = GetTable<T>();
                return (from t in table
                        select t).Where(query).SingleOrDefault();
            }
            catch (Exception ex)
            {
                throw ex;
            }
        }




        #endregion

        ///<summary>
        ///获取主键，此方式只适用于edmx数据表结构
        ///</summary>
        ///<param name="infos"></param>
        ///<returns></returns>
        private string getPrimaryKey(PropertyInfo[] infos)
        {
            string columnName = string.Empty;
            foreach (PropertyInfo propertyInfo in infos)
            {
                object[] customInfos = propertyInfo.GetCustomAttributes(typeof(EdmScalarPropertyAttribute), true);
                if (customInfos == null
               || customInfos.Length == 0)
                    return string.Empty;

                EdmScalarPropertyAttribute limit = customInfos.GetValue(0) as EdmScalarPropertyAttribute;
                if (limit.EntityKeyProperty)
                {
                    return columnName = propertyInfo.Name;
                }
            }
            return columnName;

        }

        //protected override string GetEntitySetName()
        //{
        //    return context.Products.EntitySet.Name;


        //}

        #region 更新实体
        public bool Update<T>(T entity, string PrimaryKey, object PrimaryKeyValue) where T : EntityObject
        {
            Type type = typeof(T);
            string strName = entities.Connection.ConnectionString.Replace("name=", "");
            EntityKey key = null;
            try
            {
                entity.EntityKey = entities.CreateEntityKey(type.Name, entity);
            }
            catch (Exception ex)
            {

            }

            try
            {
                key = entity.EntityKey;//new EntityKey("Entities." + type.Name, PrimaryKey, PrimaryKeyValue);
            }
            catch (Exception ex) 
            { }
            object propertyValue = http://www.mamicode.com/null;>