方案一：
In web.config (StateServer mode, with a one minute timeout to make testing easier):
<sessionState
mode="StateServer"
stateConnectionString="tcpip=127.0.0.1:42424"
sqlConnectionString="data source=127.0.0.1;user id=sa;password=letmein"
cookieless="false"
timeout="1"
/> |
In Global.asax.cs:
protected void Application_PreRequestHandlerExecute(Object sender, EventArgs e)
{
// Let's write a message to show this got fired---
Response.Write("SessionID: " +Session.SessionID.ToString() + "User key: " +(string)Session["user"]);
if(Session["user"]!=null) // e.g. this is after an initial logon
{
string sKey=(string)Session["user"];
// Accessing the Cache Item extends the Sliding Expiration automatically
string sUser=(string) HttpContext.Current.Cache[sKey];
}
} |
In your Login Page "Login" button handler:
private void Button1_Click(object sender, System.EventArgs e)
{
//validate your user here (Forms Auth or Database, for example)
// this could be a new "illegal" logon, so we need to check
// if these credentials are already in the Cache
string sKey=TextBox1.Text+TextBox2.Text;
string sUser=Convert.ToString(Cache[sKey]);
if (sUser==null || sUser==String.Empty){
// No Cache item, so sesion is either expired or user is new sign-on
// Set the cache item and Session hit-test for this user---
TimeSpan SessTimeOut=new TimeSpan(0,0,HttpContext.Current.Session.Timeout,0,0);
HttpContext.Current.Cache.Insert(sKey,sKey,null,DateTime.MaxValue,SessTimeOut,
System.Web.Caching.CacheItemPriority.NotRemovable,null);
Session["user"]=TextBox1.Text+TextBox2.Text;
// Let them in - redirect to main page, etc.
Label1.Text="<Marquee><h1>Welcome!</h1></marquee>";
}
else
{
// cache item exists, so too bad...
Label1.Text="<Marquee><h1><font color=red>ILLEGAL LOGIN ATTEMPT!!!</font></h1></marquee>";
return;
}
}
|
方案二：
public virtual void Application_Start(object sender, EventArgs e)
{
// reset the mailer indicator
Application["MailerStatus"] = "All Mailings Complete";
// initialize a datatable for users online
DataTable objUserTable = new DataTable();
objUserTable.Columns.Add("SessionID",System.Type.GetType("System.Guid"));
objUserTable.Columns.Add("PeopleID",System.Type.GetType("System.Int32"));
objUserTable.Columns.Add("ShowDetail",System.Type.GetType("System.Boolean"));
DataColumn[] pk = new DataColumn[1];
pk[0] = objUserTable.Columns[0];
objUserTable.PrimaryKey = pk;
Application["UserTable"] = objUserTable;
}
/**////
/// The Session_Start event adds user session information to
/// Application["UserTable"].
///
public virtual void Session_Start(object sender, EventArgs e)
{
Application.Lock();
//Application.Lock ();
DataTable objUserTable = (DataTable)Application["UserTable"];
DataRow objRow = objUserTable.NewRow();
Guid objGuid = Guid.NewGuid();
objRow[0] = objGuid;
Session["PfSessionID"] = objRow[0];
objRow[1] = 0;
objRow[2] = false;
objUserTable.Rows.Add(objRow);
Application["UserTable"] = objUserTable;
Application.UnLock();
}
/**////
/// The Session_End event deletes user session information from
/// Application["UserTable"].
///
public virtual void Session_End(object sender, EventArgs e)
{
Application.Lock();
DataTable objUserTable = (DataTable)Application["UserTable"];
objUserTable.Rows.Find((Guid)Session["PfSessionID"]).Delete();
Application["UserTable"] = objUserTable;
Application.UnLock();
}
方案三：
protected void Login_Click(object sender, EventArgs e)
{
try
{
//用户名
string sName = TextBox1.Text;
//生成Key
string sKey = sName + "_Login";
//得到Cache中的给定Key的值
string sUser = Convert.ToString(Cache[sKey]);
//检查是否存在
if (sUser == null || sUser == String.Empty)
{
Session["username"] = sName;
//Cache中没有该Key的项目，表明用户没有登录，或者已经登录超时
//TimeSpan 表示一个时间间隔，获取系统对session超时作的设置值
//（如果考虑到允许用户再次登陆的时间小于session超时时间，可将此值设小）
//TimeSpan SessTimeOut = new TimeSpan(0, 0, System.Web.HttpContext.Current.Session.Timeout, 0, 0);
//这里为了演示，把Cache保存时间间隔设置为了20秒
TimeSpan SessTimeOut = new TimeSpan(0, 0, 0, 20, 0);
HttpContext.Current.Cache.Insert(
sKey,
sKey,
null,
DateTime.MaxValue,
SessTimeOut,
System.Web.Caching.CacheItemPriority.NotRemovable,
null
);
//启动Timer
this.Timer1.Enabled = true;
Label1.Text = "你好！" + sName + "欢迎光临";
}
else
{
//在Cache中发现该用户的记录，表示已经登录过，禁止再次登录
Label1.Text = "对不起，你的用户身份已登陆";
return;
}
}
catch (System.Exception ex)
{
Label1.Text = ex.Message;
}
}
protected void Logout_Click(object sender, EventArgs e)
{
//用户名
string sName = TextBox1.Text;
//生成Key
string sKey = sName + "_Login";
//为了测试方便，设置了这个从Cache中移出登陆信息的方法
HttpContext.Current.Cache.Remove(sKey);
Label1.Text = Session["username"] + " 的用户登陆信息已从Cache清除!";
}
protected void TimerRunning_Tick(object sender, EventArgs e)
{
if (Session["username"] != null)
{
//用户名
string sName = TextBox1.Text;
//生成Key
string sKey = sName + "_Login";
//得到Cache中的给定Key的值
string sUser = Convert.ToString(Cache[sKey]);
TimeSpan SessTimeOut = new TimeSpan(0, 0, 0, 20, 0);
if (sUser != null)
{
HttpContext.Current.Cache.Remove(sKey);
}
HttpContext.Current.Cache.Insert(
sKey,
sKey,
null,
DateTime.MaxValue,
SessTimeOut,
System.Web.Caching.CacheItemPriority.NotRemovable,
null
);
}
else
{
this.Timer1.Enabled = false;
}
}