为什么Page.DataBind();显示的是旧数据？

Question

改成：
private void Page_Load(object sender, System.EventArgs e)
{
                           if(!IsPostBack)
                           {
string xmlpath=Server.MapPath("diary_data.xml");
dsDiary.ReadXml(xmlpath);
Page.DataBind();
XMLp=new xmlproc(Server.MapPath("diary_data.xml"));
ViewState["editkey"]=1;
                            }
}

Answer 1

private void btnWrite_Click(object sender, System.EventArgs e)
{
string xmlpath=Server.MapPath("diary_data.xml");
DateTime date=System.DateTime.Today;
XMLp.NewDiaryItem(date,txtTitle.Text,txtWeather.Text,txtContent.Text);  
                            dsDiary.ReadXml(xmlpath);
Page.DataBind();
pnlWrite.Visible=false;
}

Answer 2

private void Page_Load(object sender, System.EventArgs e)
{
                           if(!IsPostBack)
                           {
string xmlpath=Server.MapPath("diary_data.xml");
dsDiary.ReadXml(xmlpath);
Page.DataBind();
XMLp=new xmlproc(Server.MapPath("diary_data.xml"));
ViewState["editkey"]=1;
                            }
}