MVC中單用戶登錄

把下面這段代碼放在登錄用戶驗證以后：

//用戶登錄驗證通過后判斷用戶是否重復登錄
        public void SingleUserCheck(string userid)
        {
            HttpContext httpContext = System.Web.HttpContext.Current;
            Hashtable userOnline = (Hashtable)httpContext.Application["Online"];
            if (userOnline != null)
            {
                int i = 0;
                while (i < userOnline.Count)
                {
                    IDictionaryEnumerator idE = userOnline.GetEnumerator();
                    string strKey = string.Empty;
                    while (idE.MoveNext())
                    {
                        if (idE.Value != null && idE.Value.ToString().Equals(userid))  //如果當前用戶已經登錄，
                        {
                            strKey = idE.Key.ToString();
                            userOnline[strKey] = "XXXXXX";   //將當前用 戶已經在全局變量中的值設置為XX 
                            break;
                        }
                    }
                    i++;
                }
            }
            else
            {
                userOnline = new Hashtable();
            }
            userOnline[httpContext.Session.SessionID] = userid;  //初始化當前用戶的  sessionid
            httpContext.Application.Lock();
            httpContext.Application["Online"] = userOnline;
            httpContext.Application.UnLock();
        }

添加驗證特性類，自動讓已經登錄的用戶下線：

using System.Collections;

namespace System.Web.Mvc
{
    public  class SingleUserAuthorize:AuthorizeAttribute
    {
        protected override bool AuthorizeCore(HttpContextBase httpContext)
        {
            Hashtable userOnline = (Hashtable)(httpContext.Application["Online"]);
            if(userOnline!=null)
            {
                IDictionaryEnumerator idE=userOnline.GetEnumerator();
                string strkey=string.Empty;
                if(userOnline.Count>0)
                {
                    while(idE.MoveNext())
                    {
                        //登錄時判斷保存的session是否與當前頁面的session相同
                        if (userOnline.Contains(httpContext.Session.SessionID))
                        {
                            if (idE.Key != null && idE.Key.ToString().Equals(httpContext.Session.SessionID))
                            {
                                //判斷當前session保存的值是否為被注銷值
                                if (idE.Value != null && "XXXXXX".Equals(idE.Value.ToString()))
                                {
                                    //驗證被注銷則清空session
                                    userOnline.Remove(httpContext.Session.SessionID);
                                    httpContext.Application.Lock();
                                    httpContext.Application["Online"] = userOnline;
                                    httpContext.Response.Write("<script>alert('你的帳號在別處登錄，你被強迫下線！');location.href='/Load';</script>");
                                    httpContext.Response.End();  
                                    return false;
                                }
                            }
                        }
                        else
                        {
                            return false;
                        }
                    }
                    return true;
                }
                else
                {
                    return false;
                }
            }
            return false; 
        }
    }
}

驗證的時候在控制器里添加：

[SingleUserAuthorize]

最后在Global.asax.cs里添加如下代碼：

//單點登錄代碼開始
        protected void Session_Start(object sender, EventArgs e) { }
        protected void Session_End(object sender, EventArgs e)
        {
            Hashtable hOnline = (Hashtable)Application["Online"];
            if (hOnline[Session.SessionID] != null)
            {
                hOnline.Remove(Session.SessionID);
                Application.Lock();
                Application["Online"] = hOnline;
                Application.UnLock();
            }
        }
        //單點登錄代碼結束