Entity Framework底层操作封装(2)

在http://blog.csdn.net/jacky4955/article/details/9138411（http://blog.csdn.net/jacky4955/article/details/9138411）里面，是对操作底层的封装，但对于偶来说，其实并不满意。因为操作还是显得太过繁琐，每一次都得去实现基础的几个方法，即使他的代码很少，这个也是一种浪费，作为一个攻城师，坚决不做码农，不去重复同样的工作。于是针对DAL的数据操作做了一个父类。

上代码：

using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Linq.Expressions;using System.Data.Objects.DataClasses;using System.Reflection;namespace NOAS.PublicOpinionMonitor.Access.Common{    public class AccessBase<T> where T : class    {        private string _strTableName;        private string _ColumsName;        private string _PrimaryKey;        private Type _PrimaryKeyType;        public AccessBase(string PrimaryKey = "", string strTableName = "", string ColumsName = "")        {            Type t = typeof(T);            if (string.IsNullOrEmpty(strTableName))            {                strTableName = t.Name; //GetType(t).ToString();            }            _strTableName = strTableName;            if (string.IsNullOrEmpty(ColumsName))            {                _ColumsName = " * ";            }            if (string.IsNullOrEmpty(PrimaryKey))            {                PropertyInfo[] infos = t.GetProperties();                _PrimaryKey = getPrimaryKey(infos);            }        }        /// <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)                {                    _PrimaryKeyType = propertyInfo.PropertyType;                    return columnName = propertyInfo.Name;                }            }            return columnName;        }        /// <summary>        /// 执行数据库操作基础类方法        /// </summary>        protected DataCommon Data = new DataCommon();        /// <summary>        /// 增加单个实体        /// </summary>        /// <param name="t"></param>        public virtual void addEntity(T t)        {            Data.InsertEntity<T>(t);        }        public virtual T getSingleEntity(Expression<Func<T, bool>> query)        {            return Data.GetSingleEntity<T>(query);        }        public virtual T getSingleEntity(object PrimaryKeyId)        {            StringBuilder strWhere = new StringBuilder();            switch (_PrimaryKeyType.Name.ToLower())            {                case "int16":                case "int32":                case "int64":                case "int":                case "decimal":                case "double":                case "float":                case "short":                    strWhere.AppendFormat(" {0}={1}", _PrimaryKey, PrimaryKeyId);                    break;                case "bool":                case "boolean":                    if ((bool)PrimaryKeyId)                    { strWhere.AppendFormat(" {0}=1", _PrimaryKey);}                    else                     { strWhere.AppendFormat(" {0}=0", _PrimaryKey); }                    break;                default:                    strWhere.AppendFormat(" {0}='{1}'", _PrimaryKey, PrimaryKeyId);                    break;            }            return getListByWhere(strWhere.ToString()).FirstOrDefault();        }        /// <summary>        /// 修改单个实体        /// </summary>        /// <param name="t"></param>        public virtual void updateEntity(T t)        {            Data.Update<T>(t);        }        /// <summary>        /// 根据条件删除信息        /// </summary>        /// <param name="query">条件</param>        public virtual void deleteEntity(Expression<Func<T, bool>> query)        {            Data.DeleteEntitys<T>(query);        }        /// <summary>        /// 根据条件获取相关监测信息表        /// </summary>        /// <param name="strWhere">Where条件</param>        /// <returns>数据集合</returns>        protected virtual List<T> getListByWhere(string strWhere)        {            StringBuilder strSql = new StringBuilder();            strSql.AppendFormat("select {1} from {0}", _strTableName, _ColumsName);            if (!string.IsNullOrEmpty(strWhere))            {                strSql.AppendFormat(" where {0}", strWhere);            }            return Data.ExecuteQuery<T>(strSql.ToString()).ToList();        }        /// <summary>        /// 获取最大主键        /// </summary>        /// <returns></returns>        protected virtual int? getMaxPrimaryKey()        {            StringBuilder strSql = new StringBuilder();            strSql.AppendFormat("select max({1}) from {0}", _strTableName, _PrimaryKey);            return Data.ExecuteQuery<int>(strSql.ToString()).FirstOrDefault();        }    }}

这样继承的子类，就自动拥有了增删改查的基础方法。