ASP.NET三层架构详解 如何实现三层架构

时间:2022-09-01 15:27:33

一、数据库

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/*==============================================================*/
/* 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

ASP.NET三层架构详解 如何实现三层架构

ASP.NET三层架构详解 如何实现三层架构

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

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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

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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

 

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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

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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

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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

 

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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

 

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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:

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<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

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<%@ 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="http://schemas.microsoft.com/intellisense/ie5">
    </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"> </td>
                  <td
                     <asp:Label id="lblTitle" runat="server"></asp:Label></td>
              </tr>
              <tr>
                  <td style="WIDTH: 173px; HEIGHT: 22px"> </td>
                  <td style="HEIGHT: 22px"
                     <asp:Label id="lblDataTime" runat="server"></asp:Label></td>
              </tr>
              <tr>
                  <td style="WIDTH: 173px"> </td>
                  <td
                     <asp:Label id="lblContent" runat="server"></asp:Label></td>
              </tr>
              <tr>
                  <td style="WIDTH: 173px"> </td>
                  <td> </td>
              </tr>
              <tr>
                  <td style="WIDTH: 173px; HEIGHT: 23px"> </td>
                  <td style="HEIGHT: 23px"> </td>
              </tr>
              <tr>
                  <td style="WIDTH: 173px"> </td>
                  <td> </td>
              </tr>
              <tr>
                  <td style="WIDTH: 173px"> </td>
                  <td> </td>
              </tr>
              <tr>
                  <td style="WIDTH: 173px"> </td>
                  <td> </td>
              </tr>
              <tr>
                  <td style="WIDTH: 173px"> </td>
                  <td
                     <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:

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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

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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(""");
                         break;
                     case '<':
                         retVal.Append("<");
                         break;
                     case '>':
                         retVal.Append(">");
                         break;
                     default:
                         retVal.Append(inputString[i]);
                         break;
                  }
              }
 
              // Replace single quotes with white space
              retVal.Replace("'", " ");
           }
 
           return retVal.ToString();
          
       }
        
    }
}

以上就是ASP.NET三层架构的全部内容,希望对大家的学习有所帮助。