namespace MVCCommonAuth
{
  #region 功能說明
  // 舉個例子：一個網(wǎng)站有用戶系統(tǒng)、商家系統(tǒng)、網(wǎng)站后臺3個系統(tǒng)
  //可以分3個userType, user ,shop , system
  //網(wǎng)站后臺一般都有角色，如admin,employee
  //那么網(wǎng)站的角色就有 user,shop,admin,employee,但是admin和employee在一個客戶端是不能同時登陸的，所以他們是同一類用戶（system）
  #endregion

  public enum UserType
  {
    User,
    Shop,
    System
  }

  [Serializable]
  public class LoginUser
  {
    private static string DESKEY = DateTime.Now.ToString("1234MMdd");
    public int ID { get; set; }
    public string UserName { get; set; }
    public string Roles { get; set; }
    public DateTime Expires { get; set; }

    public readonly static string CookieNamePrefix = "authcookie";

    public void Login(string userType, string domain = null, string path = null)
    {
      var keyName = CookieNamePrefix + userType;
      var json = JsonConvert.SerializeObject(this);
      var value = EncryptString(json, DESKEY);

      HttpCookie cookie = new HttpCookie(keyName, value);
      cookie.Expires = Expires;
      if (!string.IsNullOrWhiteSpace(domain))
      {
        cookie.Domain = domain;
      }
      if (path != null)
      {
        cookie.Path = path;
      }
      HttpContext.Current.Items[keyName] = this;
      HttpContext.Current.Response.Cookies.Add(cookie);
    }


    /// <summary>
    /// 從cookie讀取用戶信息
    /// </summary>
    /// <param name="cookieName"></param>
    private static LoginUser BuildUser(string keyName)
    {
      var cookie = HttpContext.Current.Request.Cookies[keyName];
      if (cookie != null && !string.IsNullOrEmpty(cookie.Value))
      {
        try
        {
          var json = DecryptString(cookie.Value, DESKEY);
          var loginuser = JsonConvert.DeserializeObject<LoginUser>(json);
          if (loginuser != null)
          {
            if (loginuser.Expires >= DateTime.Now)
            {
              return loginuser;
            }
          }
        }
        catch
        {
          //do nothing
        }
      }
      return null;
    }

    public static LoginUser GetUser(string userType)
    {
      var keyName = CookieNamePrefix + userType;
      if (!HttpContext.Current.Items.Contains(keyName))
      {
        var user = BuildUser(keyName);
        HttpContext.Current.Items[keyName] = user;
        return user;
      }
      else
      {
        return HttpContext.Current.Items[keyName] as LoginUser;
      }
    }

    public static int GetUserID(string userType)
    {
      var user = GetUser(userType);
      if (user != null)
        return user.ID;
      return 0;
    }

    /// <summary>
    /// 退出cookie登錄
    /// </summary>
    public static void Logout(string userType)
    {
      var keyName = CookieNamePrefix + userType;

      HttpCookie cookie = new HttpCookie(keyName, string.Empty);
      cookie.Expires = DateTime.Now.AddMonths(-1);
      HttpContext.Current.Response.Cookies.Add(cookie);
    }


    #region 字符串加密

    /// <summary>  
    /// 利用DES加密算法加密字符串（可解密）  
    /// </summary>  
    /// <param name="plaintext">被加密的字符串</param>  
    /// <param name="key">密鑰（只支持8個字節(jié)的密鑰）</param>  
    /// <returns>加密后的字符串</returns>  
    private static string EncryptString(string plaintext, string key)
    {
      //訪問數(shù)據(jù)加密標(biāo)準(zhǔn)(DES)算法的加密服務(wù)提供程序 (CSP) 版本的包裝對象  
      DESCryptoServiceProvider des = new DESCryptoServiceProvider();
      des.Key = ASCIIEncoding.ASCII.GetBytes(key);　//建立加密對象的密鑰和偏移量  
      des.IV = ASCIIEncoding.ASCII.GetBytes(key);　 //原文使用ASCIIEncoding.ASCII方法的GetBytes方法  

      byte[] inputByteArray = Encoding.Default.GetBytes(plaintext);//把字符串放到byte數(shù)組中  

      MemoryStream ms = new MemoryStream();//創(chuàng)建其支持存儲區(qū)為內(nèi)存的流　  
      //定義將數(shù)據(jù)流鏈接到加密轉(zhuǎn)換的流  
      CryptoStream cs = new CryptoStream(ms, des.CreateEncryptor(), CryptoStreamMode.Write);
      cs.Write(inputByteArray, 0, inputByteArray.Length);
      cs.FlushFinalBlock();
      //上面已經(jīng)完成了把加密后的結(jié)果放到內(nèi)存中去  
      StringBuilder ret = new StringBuilder();
      foreach (byte b in ms.ToArray())
      {
        ret.AppendFormat("{0:X2}", b);
      }
      ret.ToString();
      return ret.ToString();
    }
    /// <summary>  
    /// 利用DES解密算法解密密文（可解密）  
    /// </summary>  
    /// <param name="ciphertext">被解密的字符串</param>  
    /// <param name="key">密鑰（只支持8個字節(jié)的密鑰，同前面的加密密鑰相同）</param>  
    /// <returns>返回被解密的字符串</returns>  
    private static string DecryptString(string ciphertext, string key)
    {
      try
      {
        DESCryptoServiceProvider des = new DESCryptoServiceProvider();

        byte[] inputByteArray = new byte[ciphertext.Length / 2];
        for (int x = 0; x < ciphertext.Length / 2; x++)
        {
          int i = (Convert.ToInt32(ciphertext.Substring(x * 2, 2), 16));
          inputByteArray[x] = (byte)i;
        }

        des.Key = ASCIIEncoding.ASCII.GetBytes(key);　//建立加密對象的密鑰和偏移量，此值重要，不能修改  
        des.IV = ASCIIEncoding.ASCII.GetBytes(key);
        MemoryStream ms = new MemoryStream();
        CryptoStream cs = new CryptoStream(ms, des.CreateDecryptor(), CryptoStreamMode.Write);

        cs.Write(inputByteArray, 0, inputByteArray.Length);

        cs.FlushFinalBlock();

        //建立StringBuild對象，createDecrypt使用的是流對象，必須把解密后的文本變成流對象  
        StringBuilder ret = new StringBuilder();

        return System.Text.Encoding.Default.GetString(ms.ToArray());
      }
      catch (Exception)
      {
        return "error";
      }
    }

    #endregion
  }
}

    [HttpPost]
    public ActionResult Login(string username,string userpass)
    {
      if (username=="admin" && userpass=="admin")
      {
        LoginUser loginuser = new LoginUser();
        loginuser.ID = 1;
        loginuser.UserName = username;
        loginuser.Roles = "Administrator";
        loginuser.Expires = DateTime.Now.AddHours(2);

        loginuser.Login("Administrator");

        return Content("登錄成功");
        //return RedirectToAction("Index", "Home");
      }

      return RedirectToAction("Login");
    }

//是否登錄
if(LoginUser.GetUserID("Administrator") > 0)
{

}
// 用戶ID
int userID=LoginUser.GetUserID("Administrator")

//獲取用戶名
string userName= LoginUser.GetUser("Administrator").UserName

  <form id="form1" runat="server">
  <script src="../Script/jquery-v1.10.2.js" type="text/javascript"></script>
  <script src="login.js" type="text/javascript"></script>
  <div class="" style="height: 160px">
    <div>
      <label for="userName">
        帳號：</label>
      <input type="text" name="userName" />
    </div>
    <div>
      <label for="password">
        密碼：</label>
      <input type="password" name="password" />
    </div>
    <input type="submit" id="btnSumit" value="登錄" />
    <p class="msg"> </p>
  </div>
  </form>

/*!
* 插件名稱：登錄插件封裝，使用方法： 
   $('#form1').login({
      url: "LoginHandler.ashx",//處理登錄驗(yàn)證邏輯的Url
      userName: $("input[name='userName']"),//用戶名輸入框
      password: $("input[name='password']"),//密碼輸入框
      msg: $(".msg"),                    //提示信息
      button: $("#btnSumit")              //提交按鈕
    }); 
*/
(function ($) {
  $.fn.login = function (option) {
    var defaults = {
      url: '/account/login/',
      msg: $(this).find('.msg'),
      userName: $(this).find("input[name='userName']"),
      password: $(this).find("input[name='password']"),
      button: $(this).find("#button")
    };
    var options = $.extend(defaults, option);
    var errMsg = {
      'inputUserName': '請輸入用戶名',
      'inputPassword': '請?zhí)顚懙卿浢艽a',
      'passwordLength': '密碼應(yīng)在6-32位字符內(nèi)',
      'noreg': '此賬號未注冊',
      'inviladUserName': '帳號不存在',
      'accountNotMatch': '賬號密碼不匹配',
      'userLocked': '帳號鎖定中，暫時無法登錄',
      'serverdown': '服務(wù)器繁忙，請稍后再試'
    };
    //提交數(shù)據(jù)
    function submit() {
      var userNameInput = $.trim(options.userName.val());
      var passwordInput = $.trim(options.password.val());
      if (userNameInput == '') {
        showMsg('登錄名不能為空');
        options.userName.focus();
        return;
      }
      if (passwordInput == '') {
        showMsg('密碼不能為空');
        options.password.focus();
        return;
      }
      $.ajax({
        type: "POST",
        url: options.url,
        data: "userName=" + userNameInput + "&password=" + passwordInput,
        success: function (msg) {
          var result = eval("[" + msg + "]")[0];
          if (result.status == "ok") {
            //登錄成功處理
            showMsg("登錄成功....");
          } else {
            showMsg(errMsg[result.status]);
          }
        }
      });
    }
    //顯示錯誤信息
    function showMsg(msg) {
      options.msg.html(msg);
    }
    //綁定按鈕事件
    options.button.bind('click', function () {
      submit();
      return false;
    });
  };
})(jQuery);

  <script type="text/javascript">
    $('#form1').login({
      url: "AjaxLogin.aspx",
      userName: $("input[name='userName']"),
      password: $("input[name='password']"),
      msg: $(".msg"),
      button: $("#btnSumit")
    });
  </script>

using System;
using System.Web;
using System.Web.UI;
namespace Whir.SiteFactory.Website.Admin.Account
{
  public partial class AjaxLogin : Page
  {
    protected void Page_Load(object sender, EventArgs e)
    {
      string status = ProcessLogin();
      Response.Clear();
      Response.Write(status);
      Response.End();
    }
    private string ProcessLogin()
    {
      try
      {
        string userName = HttpContext.Current.Request.Form["userName"];
        string password = HttpContext.Current.Request.Form["password"];
        if (string.IsNullOrEmpty(userName))
        {
          return "{status:'inputUserName'}"; //請輸入用戶名
        }
        if (string.IsNullOrEmpty(password))
        {
          return "{status:'inputPassword'}"; //請?zhí)顚懙卿浢艽a
        }
        if (password.Length < 6 || password.Length > 32)
        {
          return "{status:'passwordLength'}"; //密碼應(yīng)在6-32位字符內(nèi)
        }
        //var user = UserService.GetUserByName(userName);
        //if (user == null)
        //{
        //  return "{status:'inviladUserName'}"; //帳號不存在
        //}
        //if (user.IsLocked)
        //{
        //  return "{status:'userLocked'}"; //帳號鎖定中，暫時無法登錄
        //}
        //if (user.Password.ToLower() != password.ToMd5().ToLower())
        //{ 
        //  return "{accountNotMatch:'ok'}"; //賬號密碼不匹配
        //}
        //其他操作：
        //寫入客戶端cookie
        //登錄日志
        return "{status:'ok'}"; //登錄成功
      }
      catch (Exception ex)
      {
        return "{status:'serverdown'}"; //服務(wù)器繁忙，請稍后再試
      }
    }
  }
}