ASP.NET实现三层架构网站创建流程

1.新建项目—>Visual C#—>Web—>ASP.NET空Web应用程序  或者  新建网站—>ASP.NET空网站

2.在解决方案处右击—>新建项目—>Windows—>类库，分别创建三层架构，Model（实体层）、Dll（逻辑层）、DAL（数据层），在每一层中创建如下图。

3.创建好三层类库后，在Model类库项目上右击，选择添加—>类，并命名，如下图。

4.在创建好类之后（每一个类对应数据库中的一个表），输入private string Sname（string是数据库中字段类型，Sname是数据库中字段名，与自己的数据库表相对应），如何对private string Sname选中—>右击—>选择重构—>封装字段，然后点击确定即可，实现了对数据库中表的一个字段进行封装，其余字段封装步骤跟上述一样，在创建完之后点击工具栏处的“生成”—>生成Model即可。操作步骤如下图，我的封装后的代码如下（根据自己的数据库表进行封装）。

using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Threading.Tasks;namespace Model{    public class Users    {        private string Sname;//字段类型和字段名要与数据库对应        public string Sname1//封装后的字段        {            get { return Sname; }            set { Sname = value; }        }        private string Ssex;        public string Ssex1        {            get { return Ssex; }            set { Ssex = value; }        }        private string Snumber;        public string Snumber1        {            get { return Snumber; }            set { Snumber = value; }        }        private string Sgrade;        public string Sgrade1        {            get { return Sgrade; }            set { Sgrade = value; }        }        private string Steacher;        public string Steacher1        {            get { return Steacher; }            set { Steacher = value; }        }        private string Sid;        public string Sid1        {            get { return Sid; }            set { Sid = value; }        }    }}

5.对DAL层进行代码的编写，主要分为：（1）数据库连接函数，（2）执行sql语句函数，（3）sql语句书写和相应参数存储函数，注意：要在文件头部引用using System.Data; using System.Data.SqlClient; using Model; 前两个是asp.net集成的数据库操作库，调用其中相关函数、变量即可，最后一个是我们自己创建的Model类（在使用using Model命令之前需要将Model这个类在DAL这个项目中引用，在DAL项目中的“引用”处右击，选择添加引用，选择项目找到Model这个项目类确定即可）。其中sql语句执行函数根据返回类型不同有多种，自己可查相关资料学习，sql语句中相应字段实参的存储、传递方法也多种，自己可查相关资料学习，我的DAL代码如下。

using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Threading.Tasks;using System.Data;using System.Data.SqlClient;using Model;namespace DAL{    public class UserService    {        //连接数据库        public static SqlConnection connection;        public static SqlConnection Connection        {            get            {                if (connection == null)                {                    //远程连接数据库命令（前提远程数据库服务器已经配置好允许远程连接）                    string strConn = @"Data Source=172.18.72.158;Initial Catalog=WebKuangjia;User ID=sa;Password=LIwei123;Persist Security Info=True";                    //连接本地数据库命令                    //string strConn = @"Data Source=.;Initial Catalog=WebKuangjia;Integrated Security=True";                    connection = new SqlConnection(strConn);                    connection.Open();                }                else if (connection.State == ConnectionState.Closed)                {                    connection.Open();                }                else if (connection.State == ConnectionState.Broken)                {                    connection.Close();                    connection.Open();                }                return connection;            }        }        //执行sql语句,返回被修改行数        public static int ExecuteCommand(string commandText, CommandType commandType, SqlParameter[] para)        {            SqlCommand cmd = new SqlCommand();            cmd.Connection = Connection;            cmd.CommandText = commandText;            try            {                if (para != null)                {                    cmd.Parameters.AddRange(para);                }                return cmd.ExecuteNonQuery();            }            catch (Exception e)            {                throw new Exception(e.Message);            }            finally            {                connection.Close();                cmd.Dispose();            }        }        //执行sql语句,返回数据库表        public static DataTable GetDataTable(string commandText, CommandType commandType, SqlParameter[] para)        {            SqlCommand cmd = new SqlCommand();            cmd.Connection = Connection;            cmd.CommandText = commandText;            cmd.CommandType = commandType;            try            {                if (para != null)                {                    cmd.Parameters.AddRange(para);                }                SqlDataAdapter da = new SqlDataAdapter(cmd);                DataTable temp = new DataTable();                da.Fill(temp);                return temp;            }            catch (Exception e)            {                throw new Exception(e.Message);            }            finally            {                connection.Close();                cmd.Dispose();            }        }        //增加用户        public static bool AddStudent(Users user)        {            string sql = "insert into Student(Sname,Ssex,Snumber,Sgrade,Steacher)" + "values(@name,@sex,@number,@grade,@teacher)";//sql语句字符串            if (user.Ssex1==null)            {                user.Ssex1 = "";            }            if (user.Sgrade1 == null)            {                user.Sgrade1= "";            }            if (user.Steacher1 == null)            {                user.Steacher1 = "";            }            SqlParameter[] para = new SqlParameter[]//存储相应参数的容器            {                new SqlParameter("@name",user.Sname1),                new SqlParameter("@sex",user.Ssex1),                new SqlParameter("@number",user.Snumber1),                new SqlParameter("@grade",user.Sgrade1),                new SqlParameter("@teacher",user.Steacher1),            };            int count = ExecuteCommand(sql, CommandType.Text, para);//调用执行sql语句函数            if (count>0)            {                return true;            }            else            {                return false;            }        }        //查询数据库表        public static DataTable Selecttable()        {            string sql = "select * from Student";            return GetDataTable(sql, CommandType.Text, null);        }        //删除用户        /****************删除用户返回影响行数*****************/        public static bool DeleteStudentBySnumber(string number)        {            string sql = "delete from Student where Snumber=@number";            SqlParameter[] para = new SqlParameter[]            {                new SqlParameter("@number",number),            };            int count = ExecuteCommand(sql, CommandType.Text, para);            if (count>0)            {                return true;            }            else            {                return false;            }        }        /****************删除用户返回表*****************/        public static DataTable DeleteStudentBySid(int id)        {            string sql = "delete from Student where Sid=@id";            SqlParameter[] para = new SqlParameter[]            {                new SqlParameter("@id",id),            };            return GetDataTable(sql, CommandType.Text, para);        }        //修改用户        public static bool ModifyStudent(Users user)        {            string sql = "update Student set Sname=@name,Ssex=@sex,Snumber=@number,Sgrade=@grade,Steacher=@teacher where Sid=@id";            SqlParameter[] para = new SqlParameter[]             {                new SqlParameter("@name",user.Sname1),                new SqlParameter("@sex",user.Ssex1),                new SqlParameter("@number",user.Snumber1),                new SqlParameter("@grade",user.Sgrade1),                new SqlParameter("@teacher",user.Steacher1),                new SqlParameter("@id",user.Sid1),             };            int count = ExecuteCommand(sql, CommandType.Text, para);            if (count > 0)            {                return true;            }            else            {                return false;            }        }        //查询用户        public static bool QueryStudent(string number)        {            string sql = "select * from Student where Snumber=@number";            SqlParameter[] para = new SqlParameter[]            {                new SqlParameter("@number",number),            };            int count = ExecuteCommand(sql, CommandType.Text, para);            if (count>0)            {                return true;            }            else            {                return false;            }        }    }}

6.Dll层（逻辑层），只是一个中间层，负责参数的传递和调用DAL中的函数，注意头文件需要包含：using System.Data;using System.Data.SqlClient;using Model;using DAL;
将Model和DAL类进行包含（先引用这两个类，引用方法在步骤五中已经介绍），Dll层每个函数的返回类型需要与DAL中相应函数的返回类型一致，我的Dll代码如下。

using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Threading.Tasks;using System.Data;using System.Data.SqlClient;using Model;using DAL;namespace Dll{    public class UserManage    {        public static bool add(Users user)        {            return UserService.AddStudent(user);        }        public static bool delete(string number)        {            return UserService.DeleteStudentBySnumber(number);        }        public static bool xiugai(string number)        {            return UserService.QueryStudent(number);        }        public static bool modify(Users user)        {            return UserService.ModifyStudent(user);        }        public static bool select(string number)        {            return UserService.QueryStudent(number);        }        public static DataTable table()        {            return UserService.Selecttable();        }        public static DataTable deletebyid(int id)        {            return UserService.DeleteStudentBySid(id);        }    }}

7.在三层架构文件创建成功之后，只需要在前台引用Model和Dll即可，在using中添加using System.Data;using System.Data.SqlClient;using Model;using Dll;，剩余的就是控件的使用了，我用的是gridview控件进行数据表的操作，关于gridview控件的详细使用参考http://blog.csdn.net/21aspnet/article/details/1540301。我的前台代码如下。

using System;using System.Collections.Generic;using System.Linq;using System.Web;using System.Web.UI;using System.Web.UI.WebControls;using System.Data;using System.Data.SqlClient;using Model;using Dll;namespace WebKuangJia{    public partial class index : System.Web.UI.Page    {        protected void Page_Load(object sender, EventArgs e)        {           if (!IsPostBack)//初次加载该页            {                gvbind();           }        }        protected void GridView1_RowDeleting(object sender, GridViewDeleteEventArgs e)        {            string number = GridView1.Rows[e.RowIndex].Cells[3].Text;            UserManage.delete(number);           // GridView1.DataBind();            gvbind();        }        protected void GridView1_SelectedIndexChanging(object sender, GridViewSelectEventArgs e)        {            GridView1.SelectedIndex = e.NewSelectedIndex;            //GridView1.DataBind();            gvbind();        }        protected void GridView1_RowEditing(object sender, GridViewEditEventArgs e)        {           GridView1.EditIndex = e.NewEditIndex;           // GridView1.DataBind();           gvbind();        }        protected void GridView1_RowUpdating(object sender, GridViewUpdateEventArgs e)        {            Users us = new Users();            us.Sid1 = GridView1.DataKeys[e.RowIndex].Value.ToString();//获取编辑行的数据主键值//((TextBox)GridView1.Rows[e.RowIndex].Cells[0].Controls[0]).Text;//[0].Controls[0]).Text;            us.Sname1 = ((TextBox)GridView1.Rows[e.RowIndex].Cells[1].Controls[0]).Text.ToString().Trim();//获取编辑行的第1列的textbox控件中的内容赋值给Users对象us的Sname1封装字段            us.Ssex1 = ((TextBox)GridView1.Rows[e.RowIndex].Cells[2].Controls[0]).Text.ToString().Trim();            us.Snumber1 = ((TextBox)GridView1.Rows[e.RowIndex].Cells[3].Controls[0]).Text.ToString().Trim();            us.Sgrade1 = ((TextBox)GridView1.Rows[e.RowIndex].Cells[4].Controls[0]).Text.ToString().Trim();            us.Steacher1 = ((TextBox)GridView1.Rows[e.RowIndex].Cells[5].Controls[0]).Text.ToString().Trim();            if (UserManage.modify(us))            {               GridView1.EditIndex = -1;               //GridView1.DataBind();               gvbind();            }            else            {                Response.Write("<script>alert('修改失败!')</script>");            }        }        protected void GridView1_RowCancelingEdit(object sender, GridViewCancelEditEventArgs e)        {            GridView1.EditIndex = -1;           // GridView1.DataBind();            gvbind();        }        private void gvbind()        {            DataTable list;//声明表变量            list = UserManage.table();            GridView1.DataSource = list;            GridView1.DataKeyNames = new string[] { "Sid" };//主键            GridView1.DataBind();        }    }}

8.按照上述步骤即实现了网站的创建和数据的增删改查操作，其余网站的功能和上述类型，只需要添加相应的Model子类、Dll子类和DAL子类即可（所说的子类是在类库项目中添加的类而已，并进行相应代码的书写），我的数据库表如下，前台测试如下。