ASP.NET里的底层类要怎么编写啊？JY进哦~！求教~！

using System;
using System.Data;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using jgsbTableAdapters;

/// <summary>
/// jgsb 的摘要说明
/// </summary>
[System.ComponentModel.DataObject]
public class Jg_yjmb
{
public Jg_yjmb()
{
//
// TODO: 在此处添加构造函数逻辑
//
}

private jg_yjmbTableAdapter _jgyjmbAdp = null;
protected jg_yjmbTableAdapter JgyjmbAdp
{
get
{
if (_jgyjmbAdp == null)
{
_jgyjmbAdp = new jg_yjmbTableAdapter();

}
return _jgyjmbAdp;
}
}

public jgsb.jg_yjmbDataTable GetAllData()