asp.net三层架构详解

 
/*==============================================================*/
/* DBMS name:      Microsoft SQL Server 2000                    */
/*==============================================================*/
 
 
if exists (select 1
            from sysobjects
           where id = object_id('newsContent')
            and   type = 'U')
   drop table newsContent
go
 
 
/*==============================================================*/
/* Table: newsContent                                            */
/*==============================================================*/
create table newsContent (
   ID           int              identity(1,1)   primary key,
   Title          nvarchar(50)     not null,
   Content       ntext            not null,
   AddDate      datetime         not null,
  CategoryID    int              not null
)
go
 
 
 
 
二、项目文件架构
实现步骤为：4-3-6-5-2-1
 
ID 
项目 
描述 
用途 
项目引用关系 
实例所需文件 
相关方法
 
1 
Web 
表现层 
Web页和控件 
引用BLL 
WebUI.aspx
WebUI.aspx.cs 
 
GetContent()
 
2 
BLL 
业务逻辑层 
业务逻辑组件 
引用 IDAL，Model，使用DALFactory创建实例 
Content.cs 
ContentInfo GetContentInfo(int id)
 
3 
IDAL 
数据访问层接口定义 
每个DAL实现都要实现的一组接口 
引用 Model 
IContent.cs 
ContentInfo GetContentInfo(int id)
 
4 
Model 
业务实体 
传递各种数据的容器 
无引用 
ContentInfo.cs 
 
 
5 
DALFactory 
数据层的抽象工厂 
创建反射，用来确定加载哪一个数据库访问程序集的类 
引用IDAL，通过读取web.config里设置的程序集，加载类的实例，返回给BLL使用。 
Content.cs 
IDAL.Icontent create()
 
6 
SQLServerDAL 
SQLServer数据访问层 
Microsoft SQL Server特定的Pet Shop DAL实现，使用了IDAL接口 
引用 Model和IDAL，被DALFactory加载的程序集，实现接口里的方法。 
SqlHelper.cs
 
 
 
Content.cs 
SqlDataReader ExecuteReader()
PrepareCommand()
ContentInfo GetContentInfo(int id)
 
OracleDAL 
Oracle数据访问层    
 
7 
DBUtility 
数据库访问组件基础类 
GetSqlServerConnectionString得到数据库连接字符串，也可省去该项目，在SQLServerDAL.SqlHelper中用static readonly string SqlConnectionString代替。 
无引用 
  
 
 
实现步骤过程
1、创建Model，实现业务实体。
2、创建IDAL，实现接口。
3、创建SQLServerDAL，实现接口里的方法。
4、增加web.config里的配置信息，为SQLServerDAL的程序集。
5、创建DALFactory，返回程序集的指定类的实例。
6、创建BLL，调用DALFactory，得到程序集指定类的实例，完成数据操作方法。
7、创建WEB，调用BLL里的数据操作方法。
注意：
1、web.config里的程序集名称必须与SQLServerDAL里的输出程序集名称一致。
2、DALFactory里只需要一个DataAccess类，可以完成创建所有的程序集实例。
3、项目创建后，注意修改各项目的默认命名空间和程序集名称。
4、注意修改解决方案里的项目依赖。
5、注意在解决方案里增加各项目引用。
 
三、各层间的访问过程
1、传入值，将值进行类型转换(为整型)。
2、创建BLL层的content.cs对象c，通过对象c访问BLL层的方法GetContentInfo(ID)调用BLL层。
3、BLL层方法GetContentInfo(ID)中取得数据访问层SQLServerDAL的实例,实例化IDAL层的接口对象dal，这个对象是由工厂层DALFactory创建的，然后返回IDAL层传入值所查找的内容的方法dal.GetContentInfo(id)。
4、数据工厂通过web.config配置文件中给定的webdal字串访问SQLServerDAL层，返回一个完整的调用SQLServerDAL层的路径给 BLL层。
5、到此要调用SQLServerDAL层，SQLServerDAL层完成赋值Model层的对象值为空，给定一个参数，调用SQLServerDAL层的SqlHelper的ExecuteReader方法,读出每个字段的数据赋值给以定义为空的Model层的对象。
6、SqlHelper执行sql命令，返回一个指定连接的数据库记录集，在这里需要引用参数类型，提供为打开连接命令执行做好准备PrepareCommand。
7、返回Model层把查询得到的一行记录值赋值给SQLServerDAL层的引入的Model层的对象ci，然后把这个对象返回给BLL。
8、回到Web层的BLL层的方法调用,把得到的对象值赋值给Lable标签，在前台显示给界面
 
四、项目中的文件清单
 
1、DBUtility项目
(1)connectionInfo.cs
 
using System;
using System.Configuration;
 
namespace Utility
{
       /// <summary>
       /// ConnectionInfo 的摘要说明。
       /// </summary>
       public class ConnectionInfo
       {
              public static string GetSqlServerConnectionString()
              {
                     return ConfigurationSettings.AppSettings["SQLConnString"];
              }
       }
}
 
 
2、SQLServerDAL项目
（1）SqlHelper.cs抽象类
 
using System;
using System.Data;
using System.Data.SqlClient;
using DBUtility;
 
namespace SQLServerDAL
{
       /// <summary>
       /// SqlHelper 的摘要说明。
       /// </summary>
       public abstract class SqlHelper
       {
              public static readonly string CONN_STR = ConnectionInfo.GetSqlServerConnectionString();
 
              /// <summary>
              /// 用提供的函数，执行SQL命令，返回一个从指定连接的数据库记录集
              /// </summary>
              /// <remarks>
              /// 例如：
              /// SqlDataReader r = ExecuteReader(connString, CommandType.StoredProcedure, "PublishOrders", new SqlParameter("@prodid", 24));
              /// </remarks>
              /// <param name="connectionString">SqlConnection有效的SQL连接字符串</param>
              /// <param name="commandType">CommandType：CommandType.Text、CommandType.StoredProcedure</param>
              /// <param name="commandText">SQL语句或存储过程</param>
              /// <param name="commandParameters">SqlParameter[]参数数组</param>
              /// <returns>SqlDataReader：执行结果的记录集</returns>
              public static SqlDataReader ExecuteReader(string connString, CommandType cmdType, string cmdText, params SqlParameter[] cmdParms)
              {
                     SqlCommand cmd = new SqlCommand();
                     SqlConnection conn = new SqlConnection(connString);
 
                     // 我们在这里用 try/catch 是因为如果这个方法抛出异常，我们目的是关闭数据库连接，再抛出异常，
                     // 因为这时不会有DataReader存在，此后commandBehaviour.CloseConnection将不会工作。
                     try
                     {
                            PrepareCommand(cmd, conn, null, cmdType, cmdText, cmdParms);
                            SqlDataReader rdr = cmd.ExecuteReader(CommandBehavior.CloseConnection);
                            cmd.Parameters.Clear();
                            return rdr;
                     }
                     catch
                     {
                            conn.Close();
                            throw;
                     }
              }
 
 
              /// <summary>
              /// 为执行命令做好准备：打开数据库连接，命令语句，设置命令类型（SQL语句或存储过程），函数语取。
              /// </summary>
              /// <param name="cmd">SqlCommand 组件</param>
              /// <param name="conn">SqlConnection 组件</param>
              /// <param name="trans">SqlTransaction 组件，可以为null</param>
              /// <param name="cmdType">语句类型：CommandType.Text、CommandType.StoredProcedure</param>
              /// <param name="cmdText">SQL语句，可以为存储过程</param>
              /// <param name="cmdParms">SQL参数数组</param>
              private static void PrepareCommand(SqlCommand cmd, SqlConnection conn, SqlTransaction trans, CommandType cmdType, string cmdText, SqlParameter[] cmdParms)
              {
 
                     if (conn.State != ConnectionState.Open)
                            conn.Open();
 
                     cmd.Connection = conn;
                     cmd.CommandText = cmdText;
 
                     if (trans != null)
                            cmd.Transaction = trans;
 
                     cmd.CommandType = cmdType;
 
                     if (cmdParms != null)
                     {
                            foreach (SqlParameter parm in cmdParms)
                                   cmd.Parameters.Add(parm);
                     }
              }
       }
}
 
 
（2）Content.cs类
 
using System;
using System.Data;
using System.Data.SqlClient;
using Model;
using IDAL;
 
namespace SQLServerDAL
{
       /// <summary>
       /// Content 的摘要说明。
       /// </summary>
       public class Content:IContent
       {
 
              private const string PARM_ID = "@ID";
              private const string SQL_SELECT_CONTENT = "Select ID, Title, Content, AddDate, CategoryID From newsContent Where ID = @ID";
 
 
              public ContentInfo GetContentInfo(int id)
              {
                     //创意文章内容类
                     ContentInfo ci = null;
 
                     //创建一个参数
                     SqlParameter parm = new SqlParameter(PARM_ID, SqlDbType.BigInt, 8);
                     //赋上ID值
                     parm.Value = id;
 
                     using(SqlDataReader sdr = SqlHelper.ExecuteReader(SqlHelper.CONN_STR, CommandType.Text, SQL_SELECT_CONTENT, parm))
                     {
                            if(sdr.Read())
                            {
                                   ci = new ContentInfo(sdr.GetInt32(0),sdr.GetString(1), sdr.GetString(2),
                                          sdr.GetDateTime(3), sdr.GetInt32(4), sdr.GetInt32(5), sdr.GetString(6));
                            }
                     }
                     return ci;
              }
       }
}
 
 
 
 
3、Model项目
（1）contentInfo.cs
 
using System;
 
namespace Model
{
       /// <summary>
       /// Class1 的摘要说明。
       /// </summary>
       public class ContentInfo
       {
              private int _ID;
              private string _Content;
              private string _Title;
              private string _From;
              private DateTime _AddDate;
              private int _clsID;
              private int _tmpID;
 
              /// <summary>
              /// 文章内容构造函数
              /// </summary>
              /// <param name="id">文章流水号ID</param>
              /// <param name="content">文章内容</param>
              /// <param name="title">文章标题</param>
              /// <param name="from">文章来源</param>
              /// <param name="clsid">文章的分类属性ID</param>
              /// <param name="tmpid">文章的模板属性ID</param>
              public ContentInfo(int id,string title,string content,string from,DateTime addDate,int clsid,int tmpid )
              {
                     this._ID = id;
                     this._Content = content;
                     this._Title = title;
                     this._From = from;
                     this._AddDate = addDate;
                     this._clsID = clsid;
                     this._tmpID = tmpid;
              }
 
 
              //属性
              public int ID
              {
                     get   { return _ID; }
              }
              public string Content
              {
                     get   { return _Content; }
              }
              public string Title
              {
                     get   { return _Title; }
              }
              public string From
              {
                     get   { return _From; }
              }
              public DateTime AddDate
              {
                     get   { return _AddDate; }
              }
              public int ClsID
              {
                     get   { return _clsID; }
              }
              public int TmpID
              {
                     get   { return _tmpID; }
              }
 
 
 
       }
}
 
 
4、IDAL项目
（1）Icontent.cs
 
using System;
using Model;
 
namespace IDAL
{
       /// <summary>
       /// 文章内容操作接口
       /// </summary>
       public interface IContent
       {
              /// <summary>
              /// 取得文章的内容。
              /// </summary>
              /// <param name="id">文章的ID</param>
              /// <returns></returns>
              ContentInfo GetContentInfo(int id);
       }
}
 
 
 
5、DALFactory项目
（1）Content.cs
 
using System;
using System.Reflection;
using System.Configuration;
using IDAL;
 
namespace DALFactory
{
       /// <summary>
       /// 工产模式实现文章接口。
       /// </summary>
       public class Content
       {
              public static IDAL.IContent Create()
              {
                     // 这里可以查看 DAL 接口类。
                     string path = System.Configuration.ConfigurationSettings.AppSettings["WebDAL"].ToString();
                     string className = path+".Content";
                   
                     // 用配置文件指定的类组合
                     return (IDAL.IContent)Assembly.Load(path).CreateInstance(className);
              }
       }
}
 
 
 
6、BLL项目
（1）Content.cs
 
using System;
 
using Model;
using IDAL;
 
namespace BLL
{
       /// <summary>
       /// Content 的摘要说明。
       /// </summary>
       public class Content
       {
 
              public ContentInfo GetContentInfo(int id)
              {
 
                     // 取得从数据访问层取得一个文章内容实例
                     IContent dal = DALFactory.Content.Create();
 
                     // 用DAL查找文章内容
                     return dal.GetContentInfo(id);
              }
       }
}
 
 
 
 
7、Web项目
1、Web.config：
 
  <appSettings> 
<add key="SQLConnString" value="Data Source=localhost;Persist Security info=True;Initial Catalog=newsDB;User ID=sa;Password= " />
    <add key="WebDAL" value="SQLServerDAL" />  
 </appSettings>
 
2、WebUI.aspx
 
<%@ Page language="c#" Codebehind="WebUI.aspx.cs" AutoEventWireup="false" Inherits="Web.WebUI" %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" >
<HTML>
       <HEAD>
              <title>WebUI</title>
              <meta name="GENERATOR" Content="Microsoft Visual Studio .NET 7.1">
              <meta name="CODE_LANGUAGE" Content="C#">
              <meta name="vs_defaultClientScript" content="JavaScript">
              <meta name="vs_targetSchema" content="">
       </HEAD>
       <body MS_POSITIONING="GridLayout">
              <form id="Form1" method="post" runat="server">
                     <FONT">宋体"></FONT>
                     <table width="600" border="1">
                            <tr>
                                   <td style="WIDTH: 173px">&nbsp;</td>
                                   <td>&nbsp;
                                          <asp:Label id="lblTitle" runat="server"></asp:Label></td>
                            </tr>
                            <tr>
                                   <td style="WIDTH: 173px; HEIGHT: 22px">&nbsp;</td>
                                   <td style="HEIGHT: 22px">&nbsp;
                                          <asp:Label id="lblDataTime" runat="server"></asp:Label></td>
                            </tr>
                            <tr>
                                   <td style="WIDTH: 173px">&nbsp;</td>
                                   <td>&nbsp;
                                          <asp:Label id="lblContent" runat="server"></asp:Label></td>
                            </tr>
                            <tr>
                                   <td style="WIDTH: 173px">&nbsp;</td>
                                   <td>&nbsp;</td>
                            </tr>
                            <tr>
                                   <td style="WIDTH: 173px; HEIGHT: 23px">&nbsp;</td>
                                   <td style="HEIGHT: 23px">&nbsp;</td>
                            </tr>
                            <tr>
                                   <td style="WIDTH: 173px">&nbsp;</td>
                                   <td>&nbsp;</td>
                            </tr>
                            <tr>
                                   <td style="WIDTH: 173px">&nbsp;</td>
                                   <td>&nbsp;</td>
                            </tr>
                            <tr>
                                   <td style="WIDTH: 173px">&nbsp;</td>
                                   <td>&nbsp;</td>
                            </tr>
                            <tr>
                                   <td style="WIDTH: 173px">&nbsp;</td>
                                   <td>&nbsp;
                                          <asp:Label id="lblMsg" runat="server">Label</asp:Label></td>
                            </tr>
                     </table>
              </form>
       </body>
</HTML>
 
 
 
 
 
 
3、WebUI.aspx.cs后台调用显示：
 
using System;
using System.Collections;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Web;
using System.Web.SessionState;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.HtmlControls;
 
using BLL;
using Model;
 
namespace myWeb
{
       /// <summary>
       /// WebForm1 的摘要说明。
       /// </summary>
       public class WebUI : System.Web.UI.Page
       {
              protected System.Web.UI.WebControls.Label lblTitle;
              protected System.Web.UI.WebControls.Label lblDataTime;
              protected System.Web.UI.WebControls.Label lblContent;
              protected System.Web.UI.WebControls.Label lblMsg;
 
              private ContentInfo ci ;
 
 
              private void Page_Load(object sender, System.EventArgs e)
              {
                     if(!Page.IsPostBack)
                     {
                            GetContent("1");
                     }
              }
 
              private void GetContent(string id)
              {
                     int ID = WebComponents.CleanString.GetInt(id);
            
                     Content c = new Content();
                     ci = c.GetContentInfo(ID);
                     if(ci!=null)
                     {
                            this.lblTitle.Text = ci.Title;
                            this.lblDataTime.Text = ci.AddDate.ToString("yyyy-MM-dd");
                            this.lblContent.Text = ci.Content;
                     }
                     else
                     {
                            this.lblMsg.Text = "没有找到这篇文章";
                     }
              }
 
              #region Web 窗体设计器生成的代码
              override protected void OnInit(EventArgs e)
              {
                     //
                     // CODEGEN: 该调用是 ASP.NET Web 窗体设计器所必需的。
                     //
                     InitializeComponent();
                     base.OnInit(e);
              }
            
              /// <summary>
              /// 设计器支持所需的方法 - 不要使用代码编辑器修改
              /// 此方法的内容。
              /// </summary>
              private void InitializeComponent()
              {  
                     this.Load += new System.EventHandler(this.Page_Load);
 
              }
              #endregion
       }
}
 
 
 
4、WebComponents项目
（1）CleanString.cs
 
using System;
using System.Text;
 
namespace myWeb.WebComponents
{
       /// <summary>
       /// CleanString 的摘要说明。
       /// </summary>
       public class CleanString
       {
 
              public static int GetInt(string inputString)
              {
                     try
                     {
                            return Convert.ToInt32(inputString);
                     }
                     catch
                     {
                            return 0;
                     }
 
              }
 
 
              public static string InputText(string inputString, int maxLength)
              {
                     StringBuilder retVal = new StringBuilder();
 
                     // check incoming parameters for null or blank string
                     if ((inputString != null) && (inputString != String.Empty))
                     {
                            inputString = inputString.Trim();
 
                            //chop the string incase the client-side max length
                            //fields are bypassed to prevent buffer over-runs
                            if (inputString.Length > maxLength)
                                   inputString = inputString.Substring(0, maxLength);
 
                            //convert some harmful symbols incase the regular
                            //expression validators are changed
                            for (int i = 0; i < inputString.Length; i++)
                            {
                                   switch (inputString[i])
                                   {
                                          case '"':
                                                 retVal.Append("&quot;");
                                                 break;
                                          case '<':
                                                 retVal.Append("&lt;");
                                                 break;
                                          case '>':
                                                 retVal.Append("&gt;");
                                                 break;
                                          default:
                                                 retVal.Append(inputString[i]);
                                                 break;
                                   }
                            }
 
                            // Replace single quotes with white space
                            retVal.Replace("'", " ");
                     }
 
                     return retVal.ToString();
                   
              }
              
       }

 

 
/*==============================================================*/
/* DBMS name:      Microsoft SQL Server 2000                    */
/*==============================================================*/
 
 
if exists (select 1
            from sysobjects
           where id = object_id('newsContent')
            and   type = 'U')
   drop table newsContent
go
 
 
/*==============================================================*/
/* Table: newsContent                                            */
/*==============================================================*/
create table newsContent (
   ID           int              identity(1,1)   primary key,
   Title          nvarchar(50)     not null,
   Content       ntext            not null,
   AddDate      datetime         not null,
  CategoryID    int              not null
)
go
 
 
 
 
二、项目文件架构
实现步骤为：4-3-6-5-2-1
 
ID 
项目 
描述 
用途 
项目引用关系 
实例所需文件 
相关方法
 

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