看了2天的三层架构，其实自己以前也看过这个，可以由于没有使用过，所以对于三层架构也只是知道罢了，昨天看了一下他一些内部的具体架构，三层分别是BLL、WEB、DAL，在web接受用户请求，bll处理业务，dal处理数据库事务，下面是一个简单的例子！这是一个添加新员工的页面：

后台代码如下： usingSystem.Collections; usingSystem.Web; usingSystem.Web.Security; usingSystem.Web.UI; usingSystem.Web.UI.WebControls; usingSystem.Web.UI.WebControls.WebParts; usingSystem.Web.UI.HtmlControls; usingSystem.Text; usingMaticsoft.Common; usingLTP.Accounts.Bus; usingSystem; namespaceMaticsoft.Web.Employees {    publicpartialclassMYAdd:Page    {        PRotectedvoidPage_Load(objectsender,EventArgse)         {           }                  protectedvoidButtonOK_Click(objectsender,EventArgse)        {            stringERRM ="";            if(!PageValidate.IsNumber(Temployeeid.Text.Trim()))            {                ERRM +="输入的id不是数字，不合法！";             }            if(this.Temployeeid.Text.Trim().Length ==0)            {                ERRM +="用户id不能为空！";             }            if(ERRM !="")             {                MessageBox.Show(this, ERRM);                 ERRM ="";                return;            }           intEmployeeID =int.Parse(this.Temployeeid.Text);           /            stringEmployeesName =this.Temployeename.Text;            Maticsoft.Model.Employeesmodel =newModel.Employees();                 //新建一个在dal层Employees的model对象，用于对数据库Employees表的数据处理             model.EmployeeID = EmployeeID;                                                                 //将text里面用户输入的id数据传给model             model.EmployeesName = EmployeesName;                                                    //将text里面用户输入的name数据传给model            Maticsoft.BLL.Employeesbll =newBLL.Employees();                             //新建一个在bll层的employees对象，用于调用dal层的model对象             bll.Add(model);                                                                                                   //在bll层调用add方法添加一条数据                                                                      //////////////////////////////////////   bll层的add 方法    ///////////////////////////////////////////////////////////////////////////                  /// 增加一条数据                                              publicboolAdd(Maticsoft.Model.Employeesmodel)                                 {                                                 returndal.Add(model);                                          //调用dal层的add方法添加一条数据                                 }   ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////         //////////////////////////////////////  dal层的 add 方法    ///////////////////////////////////////////////////////////////////////////             ///增加一数据                                 publicboolAdd(Maticsoft.Model.Employeesmodel)                                 {                                                 StringBuilderstrSql=newStringBuilder();                                                 strSql.Append("insert into Employees(");                                                 strSql.Append("EmployeeID,EmployeesName)");                                                 strSql.Append(" values (");                                                 strSql.Append("@EmployeeID,@EmployeesName)");                                                 SqlParameter[] parameters = {                                                                                 newSqlParameter("@EmployeeID",SqlDbType.Int,4),                                                                                 newSqlParameter("@EmployeesName",SqlDbType.VarChar,90)};                                                 parameters[0].Value = model.EmployeeID;                                                 parameters[1].Value = model.EmployeesName;                                                   introws=DbHelperSQL.ExecuteSql(strSql.ToString(),parameters);                                                 if(rows >0)                                                 {                                                                 returntrue;                                                 }                                                 else                                                 {                                                                 returnfalse;                                                 }                                 }   ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////             Maticsoft.Common.MessageBox.ShowAndRedirect(this,"保存成功|！","MYAdd.aspx");                     //成功创建后弹出对话框，并跳转到当前页面！           }          protectedvoidButtonNo_Click(objectsender,EventArgse)        {            Response.Redirect("list.aspx");         }          } }