站外登陆的实现（BS版的无忧登陆），不支持验证码

using System;
using System.Collections.Generic;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Diagnostics;
using System.IO;

using SHDocVw;
using System.Text;
using System.Net;
using mshtml;

namespace WebApplication2
{
    public partial class login2 : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {
            string URI = "***";
            var ie = new InternetExplorer();
            object vPost, vHeaders, vFlags, vTargetFrame;
            vPost = null;
            vFlags = null;
            vTargetFrame = null;
            vHeaders = "Content-Type: application/x-www-form-urlencoded" + Convert.ToChar(10) + Convert.ToChar(13);

            ie.Visible = true;
            ie.Navigate(URI, ref vFlags, ref vTargetFrame, ref vPost, ref vHeaders);
            try
            {
                System.Threading.Thread.Sleep(1000);
                HTMLDocument doc = (HTMLDocument)ie.Document;
                HTMLInputElement keyword = (HTMLInputElement)doc.getElementById("tbUserName");
                keyword.value = "***";


                HTMLInputElement keyword1 = (HTMLInputElement)doc.getElementById("tbPassword");
                keyword1.value = "***";

                HTMLInputElement submit = (HTMLInputElement)doc.getElementById("btnLogin");
                submit.click();
            }
            catch (Exception)
            {

                return;
            }
        }
    }
}

using System;
using System.Collections.Generic;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using IELoginHelper;

namespace WebApplication2
{
    public partial class _Default : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {

           

        }

        protected void Button1_Click(object sender, EventArgs e)
        {
            IEHelper ie = new IEHelper();
            ie.OpenAVisibleBlankDocument();


            object p = null;
          

            string url = @"***";
            bool ret = ie.Navigate(url, ref p, ref p, ref p, ref p);

            ie.SetValueById("txtusername", "***");
            ie.SetValueById("txtpwd", "***");
            ie.ClickButtonByName("***");


           
        }
    }
}