三层架构怎么利用asp.net实现

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");
    }
  
  }
}