ASP.NET三层架构DAL层连接数据库的方法

Posted 2023-04-03

本人初步接触ASP三层,我知道如果在后台直接写代码
如: sqlconnection con=new sqlconnection("server=.;database=db;integrated security=true");
con.Open();
以上写出代码后确定了登录方式,数据库名称,及安全度
但是如果在三层的DAL层中创建一个DB类,这个类中写一个连接数据库的方法,将如何写?
可以举个小例子或者写段非常精简而且又实用的例子吗?
比如我们用ASP.NET只做一个网站的注册
1.注册页面有 txtName,txtPwd,txtEmail,txtQQ 和 btnLogin
2.创建 Model,BLL,DAL层
3.Model层有User类
private string txtName;
......(定义 txtPwd,txtEmail,txtQQ ---直接省略 明白的一看就懂)
public User

this.txtName=String.Empty;
......

public string TxtName

getreturn this.txtName;
setthis.txtName=Value;

......
4.BLL层调用DAL层方法这个谁都知道
5.DAL层就开始写数据库的连接数据库及增删改查的方法了
我这里不明白的就是 如何在DAL层里面的DB类中写连接数据库的语句
写出来是不是能直接连接数据库
6.还有就是如何在DAL层定义了 Select类 利用Model层的值查找数据库中是否存在的信息
7.希望写的详细点 按照我的思路写出这个小例子的Model,BLL,DAL各层的代码
虽然说精简但是一定不要省略任何代码,
8.真的非常感谢 这次出100分以示对高手你的尊重和我学三层的决心!
希望写出以上思路的整体的例子,代码量那是肯定不多的,精简但不要省略任何代码,谢谢!
如:我新建了一个 website1 三个类库 Model BLL DAL
请将 DAL的 数据库查询类Select.cs,数据库连接类DB.cs里面的所有代码都写出来 数据库需要连接,最主要的是怎么连接,前提工作?命名空间? 详细但不失精简
谢谢啊!

参考技术A 假设数据库连接字符串在web.config里配置如下
<connectionStrings>
<add name="ConnectionString" connectionString="Data Source=.;Initial Catalog=Database;Integrated Security=True"
providerName="System.Data.SqlClient" />
</connectionStrings>

对你的DAL项目右键添加System.Configuration引用(必须步骤),
添加Model项目引用
然后在DB类(假设为UserDAL.cs)
using System.Configuration;//这个必须.
using Model那个项目
public class UserDAL

public const string ConnectionString = ConfigurationManager.ConnectionStrings [ "ConnectionString" ].ConnectionString;
public int Insert(UserInfo user)// Model


SqlConnection sqlcon=new SqlConnection ( ConnectionString );
.................



BLL
添加DB和Model项目引用
using 那个DB
public class UserBLL

public int Insert(UserInfo user)

int i = UserDAL.Insert(user);

本回答被提问者采纳 参考技术B using System;
using System.Collections.Generic;
using System.Text;
using System.Data.SqlClient;
using System.Data;
using System.Configuration;

namespace SQLServerDAL

/// <summary>
/// 数据操作类DBHelper.cs
/// 创建于：2009-06-08 03-31-09
/// 作者： Administrator
/// </summary>
class DBHelper

static SqlConnection cnn;
static string cnnString ;
static DBHelper()

cnnString= ConfigurationManager.ConnectionStrings["SQLServer"].ConnectionString;


public static SqlConnection Connection

get

if(cnn==null)

cnn = new SqlConnection(cnnString);

if (cnn.State==ConnectionState.Closed)

cnn.Open();

if (cnn.State==ConnectionState.Broken)

cnn.Close();
cnn.Open();

return cnn;



public static int ExecuteCommand(string sql)

SqlCommand cmd = Connection.CreateCommand();
cmd.CommandText = sql;
int x = cmd.ExecuteNonQuery();
Connection.Close();
return x;


public static int ExecuteCommand(string procName,SqlParameter[] ps)

SqlCommand cmd = Connection.CreateCommand();
cmd.CommandText = procName;
cmd.CommandType = CommandType.StoredProcedure;
cmd.Parameters.AddRange(ps);
int x = cmd.ExecuteNonQuery();
Connection.Close();
return x;


public static DataTable GetTable(string sql)

SqlCommand cmd = Connection.CreateCommand();
cmd.CommandText = sql;
SqlDataAdapter da = new SqlDataAdapter(cmd);
DataTable dt = new DataTable();
da.Fill(dt);
return dt;


public static DataTable GetTable(string procName, SqlParameter[] ps)

SqlCommand cmd = Connection.CreateCommand();
cmd.CommandText = procName;
cmd.CommandType = CommandType.StoredProcedure;
cmd.Parameters.AddRange(ps);
SqlDataAdapter da = new SqlDataAdapter(cmd);
DataTable dt = new DataTable();
da.Fill(dt);
return dt;


public static object GetScalar(string sql)

SqlCommand cmd = Connection.CreateCommand();
cmd.CommandText = sql;
object x = cmd.ExecuteScalar();
Connection.Close();
return x;


public static object GetScalar(string procName, SqlParameter[] ps)

SqlCommand cmd = Connection.CreateCommand();
cmd.CommandText = procName;
cmd.CommandType = CommandType.StoredProcedure;
cmd.Parameters.AddRange(ps);
object x = cmd.ExecuteScalar();
Connection.Close();
return x;

参考资料：自己作主

参考技术C using System;
using System.Collections;
using System.Collections.Generic;
using System.Text;
using System.Data;
using System.Data.SqlClient;
using System.Configuration;

namespace StuDAL

public static class DBHelper


private static SqlConnection connection;
public static SqlConnection Connection

get

string connectionString = ConfigurationManager.ConnectionStrings["MyOfficeConnectionString"].ConnectionString;
connection = new SqlConnection(connectionString);
if (connection == null)

connection.Open();

else if (connection.State == System.Data.ConnectionState.Closed)

connection.Open();

else if (connection.State == System.Data.ConnectionState.Broken)

connection.Close();
connection.Open();

return connection;



public static int ExecuteCommand(string safeSql)

SqlCommand cmd = new SqlCommand(safeSql, Connection);
int result = cmd.ExecuteNonQuery();
return result;


public static int ExecuteCommand(string sql, params SqlParameter[] values)

SqlCommand cmd = new SqlCommand(sql, Connection);
cmd.Parameters.AddRange(values);
return cmd.ExecuteNonQuery();


public static string ReturnStringScalar(string safeSql)

SqlCommand cmd = new SqlCommand(safeSql, Connection);
try

string result = cmd.ExecuteScalar().ToString();
return result;

catch (Exception e)

return "0";

connection.Close();


public static int GetScalar(string safeSql)

SqlCommand cmd = new SqlCommand(safeSql, Connection);
try

int result = Convert.ToInt32(cmd.ExecuteScalar());
return result;

catch (Exception e)

return 0;

connection.Close();


public static int GetScalar(string sql, params SqlParameter[] values)

SqlCommand cmd = new SqlCommand(sql, Connection);
cmd.Parameters.AddRange(values);
int result = Convert.ToInt32(cmd.ExecuteScalar());
return result;
connection.Close();


public static SqlDataReader GetReader(string safeSql)

SqlCommand cmd = new SqlCommand(safeSql, Connection);
SqlDataReader reader = cmd.ExecuteReader();
return reader;
reader.Close();
reader.Dispose();


public static SqlDataReader GetReader(string sql, params SqlParameter[] values)

SqlCommand cmd = new SqlCommand(sql, Connection);
cmd.Parameters.AddRange(values);
SqlDataReader reader = cmd.ExecuteReader();
return reader;
reader.Close();
reader.Dispose();



public static DataTable GetDataSet(string safeSql)

DataSet ds = new DataSet();
SqlCommand cmd = new SqlCommand(safeSql, Connection);
SqlDataAdapter da = new SqlDataAdapter(cmd);
da.Fill(ds);
connection.Close();
connection.Dispose();
return ds.Tables[0];


public static DataTable GetDataSet(string sql, params SqlParameter[] values)

DataSet ds = new DataSet();
SqlCommand cmd = new SqlCommand(sql, Connection);
cmd.Parameters.AddRange(values);
SqlDataAdapter da = new SqlDataAdapter(cmd);
da.Fill(ds);
connection.Close();
connection.Dispose();
return ds.Tables[0];




参考技术D using System.Data.SqlClient;
using System.Text;
public int Add(Model.User model)

StringBuilder strSql = new StringBuilder();
strSql.Append("insert into User(");
strSql.Append("Name,pwd,Email");
strSql.Append(")");
strSql.Append(" values (");
strSql.Append("'" + model.TxtName+ "',");
strSql.Append("'" + model.txtPwd+ "',");
strSql.Append("'" + model.txtEmail+ "'");
strSql.Append(")");
return SQLHelper.getInt(strSql.ToString());


SQLHelper.cs页面
using System.Data.SqlClient;
public class SQLHelper


protected static SqlConnection connection = new SqlConnection("server=.;database=db;integrated security=true");
public int getInt(string sql)

try

if (connection.State == ConnectionState.Closed)

connection.Open();

SqlCommand command = new SqlCommand(sql, connection);
int Int = Convert.ToInt32(command.ExecuteNonQuery());
if (connection.State == ConnectionState.Open)

connection.Close();

return Int;

finally

if (connection.State == ConnectionState.Open)

connection.Close();



第5个回答  2009-06-10 进错地方了 赶紧撤

ASP.NET MVC 的三层架构 + EF数据模型

简单实现.net mvc 三层架构，并且绑定EF数据模型

1、创建 asp.net mvc应用程序作为UI层 ，3个类库（.net fromwork）分别为DAL数据访问层、BLL业务逻辑层、Model模型

2、为各层添加引用，DAL添加Model的引用、BLL添加DAL和Model的引用、UI添加BLL和Model的引用。
右键引用-添加引用-项目-勾选相应的引用点击确定

3、为Model 添加EF数据模型
步骤：右键Model-添加-新建项-数据-ADO.NET实体数据模型-下一步。。。。。

4、为UI层添加引用：EntityFramework.sqlserver
右键引用-添加引用-浏览-找到Model下的debug目录-勾选EntityFramework.sqlserver -确定

5、将Model-APP.config中的连接字符串复制到 UI层的Web.config配置中

6、在DAL中编写数据处理代码、BLL中编写业务逻辑处理方法、最后在UI中调用需要用的即可、这里不做过多演示