/// <summary>

        /// 用户点击登陆按钮进行登录操作。

        /// </summary>

        protected void btnLogin_Click(object sender, EventArgs e)

        {

            var userInfo = PrivilegeManager.GetUserInfo(strLoginID, strLoginPwd);

            if (userInfo != null)

            {

                var iPAddresses = Dns.Resolve(Dns.GetHostName()).AddressList;

                var dateTimeNow = DateTime.Now;

                if (null != iPAddresses && iPAddresses.Length > 0)

                {

                    //1表明当前帐号已经被占用，0为否

                    if (string.Equals("1", userInfo.IsUsed, StringComparison.InvariantCultureIgnoreCase) && userInfo.LastLoginTime.HasValue)

                    {

                        var diffTime = dateTimeNow - userInfo.LastLoginTime.Value;

                        var sessionTimeOut = HttpContext.Current.Session.Timeout;

                        if (diffTime.TotalMinutes < sessionTimeOut && !string.Equals(iPAddresses[0].ToString(), userInfo.LoginIPAddress, StringComparison.InvariantCultureIgnoreCase))

                        {

                            Alert.Show("对不起，您当前帐户已经被其他人使用了，请您更换其它帐号后再尝试登陆！", "登陆失败", MessageBoxIcon.Warning);

                            return;

                        }

                    }



                    //更新P_USERACCOUNT表的帐户信息为占用状态,登录地址为当前机器的IP

                    PrivilegeManager.UpdateUserAccountStatus("1", userInfo.AccountGuid, dateTimeNow, iPAddresses[0].ToString());



                    Session[ConstValue.SESSION_USER_INFO] = userInfo;

                    Response.Redirect("/default.aspx");

                }

            }

            else

            {

                Alert.Show("用户名或密码错误，请重试！");

                this.txtLoginID.Focus();

                return;

            }

        }

        protected void Application_EndRequest(object sender, EventArgs e)

        {

            var iPAddresses = Dns.Resolve(Dns.GetHostName()).AddressList;

            if (null != iPAddresses && iPAddresses.Length > 0)

            {

                var ipAddress = iPAddresses[0].ToString();

                var userAccountGuid = PrivilegeManager.GetLoginAccountGuidByIP(ipAddress);

                if (!string.IsNullOrEmpty(userAccountGuid))

                {

                    //如果收到了请求,则说明该帐号是在线状态,则更改最后登陆时间为当前时间,登陆IP为当前机器IP

                    PrivilegeManager.UpdateUserAccountStatus("1", userAccountGuid, DateTime.Now, ipAddress);

                }

            }

        }