如何让WebServer返回指定XML内容

using System;
using System.Data;
using System.Configuration;
using System.Collections;
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 localhost;

public partial class _Default : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {

    }

    protected void Button1_Click(object sender, EventArgs e)
    {
        CheckLogin objCheckLogin=new CheckLogin();
        CheckLogin.checkuser objcheckuser = new CheckLogin.checkuser();
        objcheckuser=objCheckLogin.Login(TextBox1.Text, TextBox2.Text);
        if (objcheckuser.logined) Label1.Text = objcheckuser.userid;
        else Label1.Text = "false";

    }
}

/*引用结束*/