限制帐号同时两处以上登录-ASP.NET

///登录页面
Hashtable haol = (Hashtable)Application["olTable"];
                if (haol == null)
                {
                    haol = new Hashtable();
                    Application["olTable"] = haol;
                }
                else
                {

                    HttpCookie cookie = new HttpCookie("ZInfo");//定义cookie对象以及名为Info的项  
                    if (Request.Cookies["Info"] != null)
                    {
                        Request.Cookies["Info"].Values["UserHotleID"] = SessionInclude.UserBranchId;
                        //cookie.Values.Add("UserHotleID", SessionInclude.UserBranchId);
                        Response.AppendCookie(cookie);//确定写入cookie中 
                    }
                    else
                    {
                        cookie.Values.Add("UserHotleID", SessionInclude.UserBranchId);
                        Response.AppendCookie(cookie);//确定写入cookie中 
                    }

                    //当前用户标识
                    Guid key = Guid.NewGuid();
                    Session["userKey"] = key;
                    IDictionaryEnumerator list = haol.GetEnumerator();
                    ArrayList ls = new ArrayList();
                    while (list.MoveNext())
                    {
                        if (list.Value.ToString() == SessionInclude.SessionId.Trim())
                        {
                            ls.Add(list.Key);
                            //haol.Remove(list.Key);
                        }
                    }
                    int i = ls.Count - 1;
                    while (i > -1)
                    {
                        Application.Lock();
                        haol.Remove(ls[i]);
                        Application.UnLock();
                        i = i - 1;
                    }
                    Application.Lock();
                    haol.Add(key, SessionInclude.SessionId.Trim());
                    Application["olTable"] = haol;
                    Application.UnLock();
                }

///所有页面继承类
public class BasePage : System.Web.UI.Page
{
 protected override void OnLoad(EventArgs e)
    {
        base.OnLoad(e);
    }

    override protected void OnInit(EventArgs e)
    {
        BasePageInitInfo();
    }
public void BasePageInitInfo()
    {
        try
        {
            Hashtable haol = (Hashtable)Application["olTable"];
            if (haol == null)
            {
                haol = new Hashtable();
                Application["olTable"] = haol;
            }
            else
            {
                if (Session["userKey"] != null)
                {
                    //当前用户Key
                    Guid key = new Guid(Session["userKey"].ToString());
                    IDictionaryEnumerator val = haol.GetEnumerator();
                    while (val.MoveNext())
                    {
                        if (val.Value.ToString().Trim() == SessionInclude.SessionId.Trim())
                        {
                            Guid currGuid = new Guid(val.Key.ToString());
                            if (!currGuid.Equals(key))
                            {
                                Application.Lock();
                                haol.Remove(Session["userKey"].ToString());
                                Session["userKey"] = null;
                                Application.UnLock();
                                Response.Write("<script>alert('您的帐号在别处登录，您被迫下线');window.parent.location='../Login.aspx';</script>");
                                break;
                            }
                        }
                    }
                }
                else
                {
                    //当前用户标识
                    Guid key = Guid.NewGuid();
                    Session["userKey"] = key;
                    IDictionaryEnumerator list = haol.GetEnumerator();
                    ArrayList ls = new ArrayList();
                    while (list.MoveNext())
                    {
                        if (list.Value.ToString() == SessionInclude.SessionId.Trim())
                        {
                            ls.Add(list.Key);
                            //haol.Remove(list.Key);
                        }
                    }
                    int i = ls.Count - 1;
                    while (i > -1)
                    {
                        Application.Lock();
                        haol.Remove(ls[i]);
                        Application.UnLock();
                        i = i - 1;
                    }
                    Application.Lock();
                    haol.Add(key, SessionInclude.SessionId.Trim());
                    Application["olTable"] = haol;
                    Application.UnLock();
                }
            }
        }
        catch
        {

        }

    }
｝


文章转自：http://www.cnblogs.com/elves/p/4044947.html