如何能知道某个用户现在在不在线呢??

Question

就是我在一个搜索的页面,我想将所有搜索到的用户当前在不在线给显示出来,有什么好的办法吗??

Answer 1

这跟你的网站记录用户登录的方式有关系，一般会在用户登录的时候，系统生成一个Session变量记录用户名或ID，你可以通过查询这个Session变量获取当前在线的用户信息。

Answer 2

参考http://blog.csdn.net/oec2003/archive/2008/03/06/2153817.aspx

Answer 3

不好意思  上面发错了
http://www.cnblogs.com/gaozhong98/archive/2008/10/31/1323849.html

Answer 4

   登录的时候
            if (Application["Users"] == null)
            {
                ht.Add(Convert.ToInt32(sdr["UserId"]), users);
                Application.Lock();
                Application["Users"] = ht; 
                Application.UnLock();
            }
            else
            {
                ht = Application["Users"] as Hashtable;
                ArrayList a = new ArrayList();                if (ht[Convert.ToInt32(sdr["UserId"])] == null)
                {
                    ht.Add(Convert.ToInt32(sdr["UserId"]), users);
                    Application.Lock();
                    Application["Users"] = ht;
                    Application.UnLock();
                }
            }        if (UserId > 0)
        {
            if (Application["Users"] != null)
            {
                ht = Application["Users"] as Hashtable;               ht.Remove(UserId);                Application.Lock();
                Application["Users"] = ht;
                Application.UnLock();
            }
        }

Answer 5

可以很多方法 像MemberShip 类 、session。
也可建个临时表 来存储在线用户，可用过数据库等

Answer 6

参考
http://www.cnblogs.com/kokoliu/archive/2007/01/11/618144.html
http://www.cnblogs.com/mrcooldog/archive/2008/09/18/936211.html
http://www.cnblogs.com/dagon007/articles/114724.html
http://www.cnblogs.com/cncxz/archive/2008/11/25/949255.html

Answer 7

我也看了···可是怎么用呢···？？其实我觉得，如果再用户登录的时候，用 Application 记录也好，用 数据库记录也好，都可以，可是，如果用户是非正常退出的，或直接关掉电源的，或掉线的，这样我们就没法获得他推出的事件，就没有办法去删除Application 的记录，或数据库记录，怎么办呢···有什么好办法吗··？？

Answer 8

实现用户是否在线代码 public class OnlineManage{    private static OnlineManage _instance = new OnlineManage();    //private Dictionary<int, OnlineUserInfo> _onlineUserList = new Dictionary<int, OnlineUserInfo>();    private Dictionary<string, OnlineUserInfo> _onlineSession = new Dictionary<string, OnlineUserInfo>();    public const int Timeout_Minutes = 20;  //非登录会员在线用户过期时间    public const int Timeout_Minutes_Member = 40; //登录会员在线过期时间    private OnlineManage()    {    }    public void Clear()    {        lock(this)        {            //_onlineUserList.Clear();            _onlineSession.Clear();        }    }    /// <summary>    /// 获取当前在线用户总数(包含登录和未登录的)    /// </summary>    public int Count    {        get { return _onlineSession.Count; }    }    /// <summary>    /// 在线会员数    /// </summary>    public int MemberCount    {        get        {            int iRet = 0;            lock(this)            {                foreach (string _sKey in _onlineSession.Keys)                {                    OnlineUserInfo oInfo = _onlineSession[_sKey];                    if (oInfo == null)                    {                        _onlineSession.Remove(_sKey);                    }                    else                    {                        if (oInfo.UserID>0)                        {                            iRet++;                        }                    }                }            }            return iRet;        }    }    public OnlineUserInfo this[int UserID]    {        get        {            lock(this)            {                foreach (string _sKey in _onlineSession.Keys)                {                    OnlineUserInfo oInfo = _onlineSession[_sKey];                    if (oInfo == null)                    {                        _onlineSession.Remove(_sKey);                    }                    else                    {                        if (oInfo.UserID == UserID)                        {                            return oInfo;                        }                    }                }                return null;            }        }    }    public OnlineUserInfo this[string sSessionID]    {        get        {            if (_onlineSession.ContainsKey(sSessionID))                return _onlineSession[sSessionID];            else                return null;        }    }    /// <summary>    /// 获取所有当前在线用户的ID数组    /// </summary>    public int[] OnlineUserIDs    {        get        {            lock(this)            {                List<int> ids = new List<int>();                foreach(string _sKey in _onlineSession.Keys)                {                    OnlineUserInfo oInfo = this[_sKey];                    if(oInfo!=null && oInfo.UserID>0)                    {                        ids.Add(oInfo.UserID);                    }                }                return ids.ToArray();            }        }    }    /// <summary>    /// 用户有活动，存在异常情况：    /// 1. Session未结束，但是换了用户登录    /// </summary>    /// <param name="UserID"></param>    public void UserActived(string sSessionID,int iUserID)    {        lock (this)        {            OnlineUserInfo oInfo = this[sSessionID];            if (oInfo == null)            {                oInfo = new OnlineUserInfo(sSessionID, iUserID);                _onlineSession.Add(sSessionID, oInfo);            }            else            {                if(oInfo.UserID != iUserID) //考虑同一个页面先后用别的帐号登录                {                    oInfo.UserID = iUserID;                    oInfo.LoginTime = DateTime.Now;                }                oInfo.LastActiveTime = DateTime.Now;            }        }    }    /// <summary>    /// 用户离开（未活动时间超时或者用户注销了）    /// </summary>    /// <param name="UserID"></param>    public void UserLeaved(string sSessionID,int iUserID)    {        lock(this)        {            _onlineSession.Remove(sSessionID);        }    }    /// <summary>    /// 用户离开（未活动时间超时或者用户注销了）    /// </summary>    /// <param name="sSessionID"></param>    public void UserLeaved(string sSessionID)    {        lock (this)        {            _onlineSession.Remove(sSessionID);        }    }    /// <summary>    /// 检查在线用户状态，如果发现有超时未活动的用户，将其删除    /// </summary>    public void CheckOnlineUsers()    {        lock(this)        {            //1.先查询出需要删除的Key列表            List<string> _removeKeys = new List<string>();            foreach (KeyValuePair<string, OnlineUserInfo> kvp in _onlineSession)            {                OnlineUserInfo oInfo = kvp.Value;                string _sKey = kvp.Key;                if(oInfo == null)                {                    _removeKeys.Add(_sKey);                }                else                {                    if(oInfo.UserID>0) //登录会员                    {                        if (oInfo.NoActiveMinutes > Timeout_Minutes_Member)                        {                            _removeKeys.Add(_sKey);                        }                    }                    else //未登录会员                    {                        if (oInfo.NoActiveMinutes > Timeout_Minutes)                        {                            _removeKeys.Add(_sKey);                        }                    }                }            }            //2.从容器中删除这些Key            foreach (string _key in _removeKeys)            {                _onlineSession.Remove(_key);            }            _removeKeys.Clear();        }    }    /// <summary>    /// 获取唯一实例    /// </summary>    /// <returns></returns>    public static OnlineManage GetInstance()    {        return _instance;    }}/// <summary>/// 在线用户信息类/// </summary>public class OnlineUserInfo{    public int UserID;    public string SessionID;    public DateTime LoginTime;    public DateTime LastActiveTime;    /// <summary>    /// 构造函数，用于用户新登录时创建用户在线条目    /// </summary>    /// <param name="iUserID">活动的用户ID</param>    /// <param name="dtLoginTime">用户活动时间</param>    public OnlineUserInfo(int iUserID,DateTime dtLoginTime)    {        UserID = iUserID;        SessionID = "";        LoginTime = dtLoginTime;        LastActiveTime = dtLoginTime;    }    /// <summary>    /// 构造函数，用于用户新登录时创建用户在线条目    /// </summary>    /// <param name="iUserID">活动的用户ID</param>    /// <param name="dtLoginTime">用户活动时间</param>    public OnlineUserInfo(string sSessionID, int iUserID)    {        UserID = iUserID;        LoginTime = DateTime.Now;        LastActiveTime = DateTime.Now;        SessionID = sSessionID;    }    /// <summary>    /// 用户初次进来并创建了新Session    /// </summary>    /// <param name="sSessionID"></param>    public OnlineUserInfo(string sSessionID)    {        UserID = 0;        LoginTime = DateTime.Now;        LastActiveTime = DateTime.Now;        SessionID = sSessionID;    }    /// <summary>    /// 获取该用户的未活动时长（分钟数）    /// </summary>    public int NoActiveMinutes    {        get        {            TimeSpan dtSpan = DateTime.Now.Subtract(LastActiveTime);            return (int)dtSpan.TotalMinutes;        }    }    /// <summary>    /// 获取该用户的在线时长（分钟数）    /// </summary>    public int OnlineMinutes    {        get        {            TimeSpan dtSpan = DateTime.Now.Subtract(LoginTime);            return (int)dtSpan.TotalMinutes;        }    }}

Answer 9

实现用户是否在线代码 public class OnlineManage{    private static OnlineManage _instance = new OnlineManage();    //private Dictionary<int, OnlineUserInfo> _onlineUserList = new Dictionary<int, OnlineUserInfo>();    private Dictionary<string, OnlineUserInfo> _onlineSession = new Dictionary<string, OnlineUserInfo>();    public const int Timeout_Minutes = 20;  //非登录会员在线用户过期时间    public const int Timeout_Minutes_Member = 40; //登录会员在线过期时间    private OnlineManage()    {    }    public void Clear()    {        lock(this)        {            //_onlineUserList.Clear();            _onlineSession.Clear();        }    }    /// <summary>    /// 获取当前在线用户总数(包含登录和未登录的)    /// </summary>    public int Count    {        get { return _onlineSession.Count; }    }    /// <summary>    /// 在线会员数    /// </summary>    public int MemberCount    {        get        {            int iRet = 0;            lock(this)            {                foreach (string _sKey in _onlineSession.Keys)                {                    OnlineUserInfo oInfo = _onlineSession[_sKey];                    if (oInfo == null)                    {                        _onlineSession.Remove(_sKey);                    }                    else                    {                        if (oInfo.UserID>0)                        {                            iRet++;                        }                    }                }            }            return iRet;        }    }    public OnlineUserInfo this[int UserID]    {        get        {            lock(this)            {                foreach (string _sKey in _onlineSession.Keys)                {                    OnlineUserInfo oInfo = _onlineSession[_sKey];                    if (oInfo == null)                    {                        _onlineSession.Remove(_sKey);                    }                    else                    {                        if (oInfo.UserID == UserID)                        {                            return oInfo;                        }                    }                }                return null;            }        }    }    public OnlineUserInfo this[string sSessionID]    {        get        {            if (_onlineSession.ContainsKey(sSessionID))                return _onlineSession[sSessionID];            else                return null;        }    }    /// <summary>    /// 获取所有当前在线用户的ID数组    /// </summary>    public int[] OnlineUserIDs    {        get        {            lock(this)            {                List<int> ids = new List<int>();                foreach(string _sKey in _onlineSession.Keys)                {                    OnlineUserInfo oInfo = this[_sKey];                    if(oInfo!=null && oInfo.UserID>0)                    {                        ids.Add(oInfo.UserID);                    }                }                return ids.ToArray();            }        }    }    /// <summary>    /// 用户有活动，存在异常情况：    /// 1. Session未结束，但是换了用户登录    /// </summary>    /// <param name="UserID"></param>    public void UserActived(string sSessionID,int iUserID)    {        lock (this)        {            OnlineUserInfo oInfo = this[sSessionID];            if (oInfo == null)            {                oInfo = new OnlineUserInfo(sSessionID, iUserID);                _onlineSession.Add(sSessionID, oInfo);            }            else            {                if(oInfo.UserID != iUserID) //考虑同一个页面先后用别的帐号登录                {                    oInfo.UserID = iUserID;                    oInfo.LoginTime = DateTime.Now;                }                oInfo.LastActiveTime = DateTime.Now;            }        }    }    /// <summary>    /// 用户离开（未活动时间超时或者用户注销了）    /// </summary>    /// <param name="UserID"></param>    public void UserLeaved(string sSessionID,int iUserID)    {        lock(this)        {            _onlineSession.Remove(sSessionID);        }    }    /// <summary>    /// 用户离开（未活动时间超时或者用户注销了）    /// </summary>    /// <param name="sSessionID"></param>    public void UserLeaved(string sSessionID)    {        lock (this)        {            _onlineSession.Remove(sSessionID);        }    }    /// <summary>    /// 检查在线用户状态，如果发现有超时未活动的用户，将其删除    /// </summary>    public void CheckOnlineUsers()    {        lock(this)        {            //1.先查询出需要删除的Key列表            List<string> _removeKeys = new List<string>();            foreach (KeyValuePair<string, OnlineUserInfo> kvp in _onlineSession)            {                OnlineUserInfo oInfo = kvp.Value;                string _sKey = kvp.Key;                if(oInfo == null)                {                    _removeKeys.Add(_sKey);                }                else                {                    if(oInfo.UserID>0) //登录会员                    {                        if (oInfo.NoActiveMinutes > Timeout_Minutes_Member)                        {                            _removeKeys.Add(_sKey);                        }                    }                    else //未登录会员                    {                        if (oInfo.NoActiveMinutes > Timeout_Minutes)                        {                            _removeKeys.Add(_sKey);                        }                    }                }            }            //2.从容器中删除这些Key            foreach (string _key in _removeKeys)            {                _onlineSession.Remove(_key);            }            _removeKeys.Clear();        }    }    /// <summary>    /// 获取唯一实例    /// </summary>    /// <returns></returns>    public static OnlineManage GetInstance()    {        return _instance;    }}/// <summary>/// 在线用户信息类/// </summary>public class OnlineUserInfo{    public int UserID;    public string SessionID;    public DateTime LoginTime;    public DateTime LastActiveTime;    /// <summary>    /// 构造函数，用于用户新登录时创建用户在线条目    /// </summary>    /// <param name="iUserID">活动的用户ID</param>    /// <param name="dtLoginTime">用户活动时间</param>    public OnlineUserInfo(int iUserID,DateTime dtLoginTime)    {        UserID = iUserID;        SessionID = "";        LoginTime = dtLoginTime;        LastActiveTime = dtLoginTime;    }    /// <summary>    /// 构造函数，用于用户新登录时创建用户在线条目    /// </summary>    /// <param name="iUserID">活动的用户ID</param>    /// <param name="dtLoginTime">用户活动时间</param>    public OnlineUserInfo(string sSessionID, int iUserID)    {        UserID = iUserID;        LoginTime = DateTime.Now;        LastActiveTime = DateTime.Now;        SessionID = sSessionID;    }    /// <summary>    /// 用户初次进来并创建了新Session    /// </summary>    /// <param name="sSessionID"></param>    public OnlineUserInfo(string sSessionID)    {        UserID = 0;        LoginTime = DateTime.Now;        LastActiveTime = DateTime.Now;        SessionID = sSessionID;    }    /// <summary>    /// 获取该用户的未活动时长（分钟数）    /// </summary>    public int NoActiveMinutes    {        get        {            TimeSpan dtSpan = DateTime.Now.Subtract(LastActiveTime);            return (int)dtSpan.TotalMinutes;        }    }    /// <summary>    /// 获取该用户的在线时长（分钟数）    /// </summary>    public int OnlineMinutes    {        get        {            TimeSpan dtSpan = DateTime.Now.Subtract(LoginTime);            return (int)dtSpan.TotalMinutes;        }    }}

Answer 10

楼上的看着有些晕，
public class OnlineManage
{
    private static OnlineManage _instance = new OnlineManage();
    //private Dictionary<int, OnlineUserInfo> _onlineUserList = new Dictionary<int, OnlineUserInfo>();
    private Dictionary<string, OnlineUserInfo> _onlineSession = new Dictionary<string, OnlineUserInfo>();    public const int Timeout_Minutes = 20;  //非登录会员在线用户过期时间
    public const int Timeout_Minutes_Member = 40; //登录会员在线过期时间    private OnlineManage()
    {
    }    public void Clear()
    {
        lock(this)
        {
            //_onlineUserList.Clear();
            _onlineSession.Clear();
        }
    }    /// <summary>
    /// 获取当前在线用户总数(包含登录和未登录的)
    /// </summary>
    public int Count
    {
        get { return _onlineSession.Count; }
    }    /// <summary>
    /// 在线会员数
    /// </summary>
    public int MemberCount
    {
        get
        {
            int iRet = 0;
            lock(this)
            {
                foreach (string _sKey in _onlineSession.Keys)
                {
                    OnlineUserInfo oInfo = _onlineSession[_sKey];
                    if (oInfo == null)
                    {
                        _onlineSession.Remove(_sKey);
                    }
                    else
                    {
                        if (oInfo.UserID>0)
                        {
                            iRet++;
                        }
                    }
                }
            }
            return iRet;
        }
    }    public OnlineUserInfo this[int UserID]
    {
        get
        {
            lock(this)
            {
                foreach (string _sKey in _onlineSession.Keys)
                {
                    OnlineUserInfo oInfo = _onlineSession[_sKey];
                    if (oInfo == null)
                    {
                        _onlineSession.Remove(_sKey);
                    }
                    else
                    {
                        if (oInfo.UserID == UserID)
                        {
                            return oInfo;
                        }
                    }
                }
                return null;
            }
        }
    }    public OnlineUserInfo this[string sSessionID]
    {
        get
        {
            if (_onlineSession.ContainsKey(sSessionID))
                return _onlineSession[sSessionID];
            else
                return null;
        }
    }    /// <summary>
    /// 获取所有当前在线用户的ID数组
    /// </summary>
    public int[] OnlineUserIDs
    {
        get
        {
            lock(this)
            {
                List<int> ids = new List<int>();
                foreach(string _sKey in _onlineSession.Keys)
                {
                    OnlineUserInfo oInfo = this[_sKey];
                    if(oInfo!=null && oInfo.UserID>0)
                    {
                        ids.Add(oInfo.UserID);
                    }
                }
                return ids.ToArray();
            }
        }
    }    /// <summary>
    /// 用户有活动，存在异常情况：
    /// 1. Session未结束，但是换了用户登录
    /// </summary>
    /// <param name="UserID"></param>
    public void UserActived(string sSessionID,int iUserID)
    {
        lock (this)
        {
            OnlineUserInfo oInfo = this[sSessionID];
            if (oInfo == null)
            {
                oInfo = new OnlineUserInfo(sSessionID, iUserID);
                _onlineSession.Add(sSessionID, oInfo);
            }
            else
            {
                if(oInfo.UserID != iUserID) //考虑同一个页面先后用别的帐号登录
                {
                    oInfo.UserID = iUserID;
                    oInfo.LoginTime = DateTime.Now;
                }
                oInfo.LastActiveTime = DateTime.Now;
            }
        }
    }    /// <summary>
    /// 用户离开（未活动时间超时或者用户注销了）
    /// </summary>
    /// <param name="UserID"></param>
    public void UserLeaved(string sSessionID,int iUserID)
    {
        lock(this)
        {
            _onlineSession.Remove(sSessionID);
        }
    }    /// <summary>
    /// 用户离开（未活动时间超时或者用户注销了）
    /// </summary>
    /// <param name="sSessionID"></param>
    public void UserLeaved(string sSessionID)
    {
        lock (this)
        {
            _onlineSession.Remove(sSessionID);
        }
    }
    /// <summary>
    /// 检查在线用户状态，如果发现有超时未活动的用户，将其删除
    /// </summary>
    public void CheckOnlineUsers()
    {
        lock(this)
        {
            //1.先查询出需要删除的Key列表
            List<string> _removeKeys = new List<string>();
            foreach (KeyValuePair<string, OnlineUserInfo> kvp in _onlineSession)
            {
                OnlineUserInfo oInfo = kvp.Value;
                string _sKey = kvp.Key;
                if(oInfo == null)
                {
                    _removeKeys.Add(_sKey);
                }
                else
                {
                    if(oInfo.UserID>0) //登录会员
                    {
                        if (oInfo.NoActiveMinutes > Timeout_Minutes_Member)
                        {
                            _removeKeys.Add(_sKey);
                        }
                    }
                    else //未登录会员
                    {
                        if (oInfo.NoActiveMinutes > Timeout_Minutes)
                        {
                            _removeKeys.Add(_sKey);
                        }
                    }
                }
            }            //2.从容器中删除这些Key
            foreach (string _key in _removeKeys)
            {
                _onlineSession.Remove(_key);
            }
            _removeKeys.Clear();
        }
    }    /// <summary>
    /// 获取唯一实例
    /// </summary>
    /// <returns></returns>
    public static OnlineManage GetInstance()
    {
        return _instance;
    }
}/// <summary>
/// 在线用户信息类
/// </summary>
public class OnlineUserInfo
{
    public int UserID;
    public string SessionID;
    public DateTime LoginTime;
    public DateTime LastActiveTime;    /// <summary>
    /// 构造函数，用于用户新登录时创建用户在线条目
    /// </summary>
    /// <param name="iUserID">活动的用户ID</param>
    /// <param name="dtLoginTime">用户活动时间</param>
    public OnlineUserInfo(int iUserID,DateTime dtLoginTime)
    {
        UserID = iUserID;
        SessionID = "";
        LoginTime = dtLoginTime;
        LastActiveTime = dtLoginTime;
    }    /// <summary>
    /// 构造函数，用于用户新登录时创建用户在线条目
    /// </summary>
    /// <param name="iUserID">活动的用户ID</param>
    /// <param name="dtLoginTime">用户活动时间</param>
    public OnlineUserInfo(string sSessionID, int iUserID)
    {
        UserID = iUserID;
        LoginTime = DateTime.Now;
        LastActiveTime = DateTime.Now;
        SessionID = sSessionID;
    }    /// <summary>
    /// 用户初次进来并创建了新Session
    /// </summary>
    /// <param name="sSessionID"></param>
    public OnlineUserInfo(string sSessionID)
    {
        UserID = 0;
        LoginTime = DateTime.Now;
        LastActiveTime = DateTime.Now;
        SessionID = sSessionID;
    }    /// <summary>
    /// 获取该用户的未活动时长（分钟数）
    /// </summary>
    public int NoActiveMinutes
    {
        get
        {
            TimeSpan dtSpan = DateTime.Now.Subtract(LastActiveTime);
            return (int)dtSpan.TotalMinutes;
        }
    }    /// <summary>
    /// 获取该用户的在线时长（分钟数）
    /// </summary>
    public int OnlineMinutes
    {
        get
        {
            TimeSpan dtSpan = DateTime.Now.Subtract(LoginTime);
            return (int)dtSpan.TotalMinutes;
        }
    }
}

Answer 11

http://www.cnblogs.com/coolylh/archive/2005/11/23/282927.aspx
ASP.NET在线用户列表 关闭浏览器 精确统计 

Answer 12

有点复杂`````难道就真的没有这个功能吗???
有没有获得所以服务器缓存中的指定 session 变量的值的功能
(比如可不可以获得服务器缓存中所有 Session["UserName"] 变量和值的集合)