这是我的代码：
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
public partial class First : System.Web.UI.Page
{ MyDataClassesDataContext mdc;
protected void Page_Load(object sender, EventArgs e)
{
mdc = new MyDataClassesDataContext();
if (!IsPostBack)
{
LoadData();
}
}
private void LoadData()
{
mdc = new MyDataClassesDataContext();
var empls = from em in mdc.Emps select em;
GVEmp.DataSource = empls;
GVEmp.DataBind();
var ddlempls = from em in mdc.Emps
select new
{
em.EmpID,
em.Ename
};
DDLEmp.DataSource = ddlempls;
DDLEmp.DataTextField = "Ename";
DDLEmp.DataValueField = "EmpID";
DDLEmp.DataBind();
DDLEmp.Items.Insert(0, "Select");
}
protected void LinkButton1_Click(object sender, EventArgs e)
{
Emp em = new Emp();
em.Ename = TxtName.Text;
em.Sal = Int32.Parse(TxtSal.Text);
mdc.Emps.InsertOnSubmit(em);
mdc.SubmitChanges();
LoadData();
LabDisp.Text = "Record Added";
}
protected void DDLEmp_SelectedIndexChanged(object sender, EventArgs e)
{ Emp empl = mdc.Emps.Single(em => em.EmpID ==Int32.Parse(DDLEmp.SelectedItem.Value));
if (empl != null)
{
TxtName0.Text = empl.Ename;
TxtSal0.Text = empl.Sal.ToString();
}
else
{
LabDisp.Text = "Data not found";
}
}
protected void LBUpd_Click(object sender, EventArgs e)
{
Emp empl = mdc.Emps.Single(em => em.EmpID ==Int32.Parse(DDLEmp.SelectedItem.Value));
if (empl != null)
{
empl.Ename = TxtName0.Text;
empl.Sal=Int32.Parse(TxtSal0.Text);
mdc.SubmitChanges();
LoadData();
LabDisp.Text = "record updated";
}
else
{
LabDisp.Text = "Data not found";
}
}
protected void LBDel_Click(object sender, EventArgs e)
{
Emp empl = mdc.Emps.Single(em => em.EmpID == Int32.Parse(DDLEmp.SelectedItem.Value));
if (empl != null)
{
mdc.Emps.DeleteOnSubmit(empl);
mdc.SubmitChanges();
LoadData();
LabDisp.Text = "record deleted";
}
else
{
LabDisp.Text = "Data not found";
}
}
}
谁能帮忙解释一下这段代码……我的一个朋友把这个和一个配置文件发给我，把一个asp页面和数据库链接起来……有些东西MyDataClassesDataContext,GVEmp.DataSource对我来说很新，我不明白其中任何一个