反射+泛型+缓存 ASP.NET的数据层通用类

 using System;

 using System.Collections.Generic;

 using System.Text;

 using System.Reflection ;

 using System.Data ;

 using BaiChang.HealBlog.Model ;

 using System.Data.SqlClient;

 using BaiChang.SqlDBUtility;

 namespace BaiChang.Middle.Front

 {

     public  class DataAccess<T>where T:new()

     {

         #region Main Part

         public static DataAccess<T> GetDataAccess()

         {

             string name = "DataAccess" + typeof(T).Name;

             DataAccess<T> tObj = Utils.CurrentPage.Cache[name] as DataAccess<T>;

             object obj = new object();

             if (tObj == null)

             {

                 Utils.CurrentPage.Cache[name] = typeof(DataAccess < T>).Assembly.CreateInstance(typeof(DataAccess<T>).Name);

                 tObj = Utils.CurrentPage.Cache[name] as DataAccess<T>;

             }

             return tObj;

         }

         public static string ToSetString(string name)

         {

             string formate = "{0}={1}";

             return string.Format(formate, name, name);

         }

         public static List<T> ToModel(SqlDataReader reader)

         {

             Dictionary<string, PropertyInfo> ps = new Dictionary<string, PropertyInfo>();

             foreach (PropertyInfo p in typeof (T).GetProperties ())

             {

                 ps.Add(p.Name, p);

             }

             List<T> ms=new List<T> ();

             while (reader.Read())

             {

                 T m = new T();

                 object[] objs = null;

                 int count = reader.GetValues(objs);

                 int i = ;

                 foreach (object o in objs)

                 {

                     ps[reader.GetName(i)].SetValue(m, o, null);

                     i++;

                 }

                 ms.Add(m);

             }

             return ms;

         }

         #region Properties

         //当前实体类型

         Type entityType;

         Type type

         {

             get

             {

                 if(entityType ==null)

                 entityType = typeof(T);

                 return entityType;

             }

         }

         //实体的所有属性

         PropertyInfo[] propertyInfos;

         PropertyInfo[] pros

         {

             get

             {

                 if (propertyInfos == null) propertyInfos = this.type.GetProperties();

                 return propertyInfos;

             }

         }

         //相对应的表名

         string _tableName=string.Empty ;

         string tableName

         {

             get

             {

                 if (_tableName == string.Empty)

                 {

                     string className = typeof(T).Name;

                     switch (className)

                     {

                         case "Users":

                         case "Role_Node_Permissions":

                             _tableName = "PE_" + className;

                         default:

                             _tableName = "HB_" + className;

                     }

                 }

             }

         }

         #endregion

         #endregion

         #region  成员方法

         /// <summary>

         /// 得到最大ID

         /// </summary>

         public int GetMaxId()

         {

             return DbHelperSQL.GetMaxID(pros[].Name , tableName);

         }

         /// <summary>

         /// 得到最大值

         /// </summary>

         /// <summary>

         /// 是否存在该记录

         /// </summary>

         public bool Exists(int ID)

         {

             StringBuilder strSql = new StringBuilder();

             strSql.Append("select count(1) from ");

             strSql.Append(tableName);

             strSql.Append(" where ");

             strSql.Append(ToSetString(pros[].Name));

             SqlParameter[] parameters = {

                     new SqlParameter("@"+pros[].Name, SqlDbType.Int,)};

             parameters[].Value = ID;

             return DbHelperSQL.Exists(strSql.ToString(), parameters);

         }

         /// <summary>

         /// 增加一条数据

         /// </summary>

         public int Add(T model)

         {

             StringBuilder strSql = new StringBuilder();

             strSql .Append ("insert into ");

             strSql .Append (tableName );

             strSql.Append(" (");

             //生成XXXvalues(XXX)

             int i=;

             foreach (PropertyInfo p in pros)

             {

                 strSql .Append (p.Name );

                 if (i != pros.Length)

                     strSql.Append(",");

                 i++;

             }

             strSql.Append(") values (");

             i = ;

             foreach (PropertyInfo p in pros)

             {

                 strSql.Append("@");

                 strSql.Append(p.Name);

                 if (i != pros.Length)

                     strSql.Append(",");

                 i++;

             }

             strSql.Append(");select @@IDENTITY");

             //生成sqlparameters

             List<SqlParameter> sqlpars = new List<SqlParameter>();

             foreach (PropertyInfo p in pros)

             {

                 SqlParameter sp = new SqlParameter("@" + p.Name, p.GetValue(model, null));

                 sqlpars.Add(sp);

             }

             object obj = DbHelperSQL.GetSingle(strSql.ToString(), sqlpars .ToArray ());

             if (obj == null)

             {

                 return ;

             }

             else

             {

                 return Convert.ToInt32(obj);

             }

         }

         /// <summary>

         /// 更新一条数据

         /// </summary>

         public void Update(T model)

         {

             StringBuilder strSql = new StringBuilder();

             strSql.Append("update ");

             strSql .Append (tableName );

             strSql .Append (" set ");

             int i=;

             foreach (PropertyInfo p in pros)

             {

                 strSql.Append(ToSetString(p.Name));

                 if(i!=pros.Length )

                     strSql .Append (",");

                 i++;

             }

             strSql.Append(" where ");

             strSql.Append(ToSetString(pros[].Name));

             //生成sqlparameters

             List<SqlParameter> sqlpars = new List<SqlParameter>();

             foreach (PropertyInfo p in pros)

             {

                 SqlParameter sp = new SqlParameter("@" + p.Name, p.GetValue(model, null));

                 sqlpars.Add(sp);

             }

             DbHelperSQL.ExecuteSql(strSql.ToString(), sqlpars .ToArray());

         }

         /// <summary>

         /// 删除一条数据

         /// </summary>

         public void Delete(int ID)

         {

             StringBuilder strSql = new StringBuilder();

             strSql.Append("delete from ");

             strSql.Append(tableName);

             strSql.Append(" where ");

             strSql.Append(ToSetString(pros[].Name));

             SqlParameter[] parameters = {

                     new SqlParameter("@"+pros [].Name, SqlDbType.Int,)};

             parameters[].Value = ID;

             DbHelperSQL.ExecuteSql(strSql.ToString(), parameters);

         }

         /// <summary>

         /// 得到一个对象实体

         /// </summary>

         public T GetModel(int ID)

         {

             StringBuilder strSql = new StringBuilder();

             strSql.Append("select  top 1 ");

             int i=;

             foreach (PropertyInfo p in pros)

             {

                 strSql.Append(ToSetString(p.Name));

                 if(i!=pros.Length )

                     strSql .Append (",");

             }

             strSql .Append (tableName );

             strSql.Append(" where  ");

             strSql.Append(ToSetString(pros[].Name));

             SqlParameter[] parameters = {

                     new SqlParameter("@"+pros[].Name, SqlDbType.Int,)};

             parameters[].Value = ID;

             List<T> ms;

             using (SqlDataReader reader = DbHelperSQL.ExecuteReader(strSql.ToString (), parameters))

             {

                  ms= ToModel(reader);

                 reader.Close();

             }

             if (ms.Count > ) return ms[];

             else return default (T);

         }

         /// <summary>

         /// 获得数据列表

         /// </summary>

         public List<T> GetList(string strWhere)

         {

             StringBuilder strSql = new StringBuilder();

             strSql.Append("select * ");

             strSql.Append(" FROM ");

             strSql.Append(tableName);

             if (strWhere.Trim() != "")

             {

                 strSql.Append(" where " + strWhere);

             }

             List<T> ms;

             using (SqlDataReader reader = DbHelperSQL.ExecuteReader(strSql.ToString ()))

             {

                 ms = ToModel(reader);

                 reader.Close();

             }

             if (ms.Count > ) return ms;

             else return null;

         }

         /// <summary>

         /// 获得前几行数据

         /// </summary>

         public List<T> GetList(int Top, string strWhere, string filedOrder)

         {

             StringBuilder strSql = new StringBuilder();

             strSql.Append("select ");

             if (Top > )

             {

                 strSql.Append(" top " + Top.ToString());

             }

             strSql.Append(" * ");

             strSql.Append(" FROM  ");

             strSql.Append(tableName);

             if (strWhere.Trim() != "")

             {

                 strSql.Append(" where " + strWhere);

             }

             strSql.Append(" order by " + filedOrder);

                         List<T> ms;

             using (SqlDataReader reader = DbHelperSQL.ExecuteReader(strSql.ToString ()))

             {

                 ms = ToModel(reader);

                 reader.Close();

             }

             if (ms.Count > ) return ms;

             else return null;

         }

          ///<summary>

          ///分页获取数据列表

          ///</summary>

         public List<T> GetList(int PageSize,int PageIndex,string strWhere)

         {

             List<T> ms=GetList(strWhere);

             int startIndex=, endIndex=;

             Utils.GetPageArea(ref startIndex, ref endIndex, PageIndex, PageSize, ms.Count);

             List<T> result = new List<T>();

             for (int i = startIndex; i <= endIndex; i++)

             {

                 result.Add(ms[i]);

             }

             return result;

         }

         #endregion  成员方法

     }

 }