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Session Start Global.asax C# ASP.NET

I have the following code:
protected void Session_Start(object sender, EventArgs e)
{
WindowsPrincipal p = Thread.CurrentPrincipal as WindowsPrincipal;
string sUserAccount = HttpContext.Current.User.Identity.Name.ToString();
HttpContext.Current.Session["WinAccount"] = sUserAccount;
}
The code is to get the windows user name. From the session_start, I want to create a session which called WinAccount. But, when I tried to call the session from one of my page (default.aspx) which is has master page on it.
Let say, on page_load:
string sWinAccount = Session["WinAccount"].ToString();
Label1.Text = sWinAccount.ToString();
The web.config looks like:
<authentication mode="Windows"/>
<identity impersonate="false"/>
<authorization>
<deny users="?"/>
</authorization>
Also, the properties of the project has been enabling the windows authentication mode.
When I run, it blanks.
Please advise.
Thank you.

Verify if the application is using Windows Authentication (check web.config). If you are providing custom or forms authentication, you will need to set user details on success handler, not the session start; and use CustomPrincipal rather than WindowsPrincipal .
If windows authentication is enabled, the user credential will be available on the very first request (session start) and can be retrieved are you mentioned in your code. Place a debugger in session start and verify if you are retrieving it properly or not.

try
string sUserAccount =System.Security.Principal.WindowsIdentity.GetCurrent().Name.Tostring();

Session_Start event fired when a new client start their very first request to the app, not when the user is logged in. So in your case, the HttpContext.Current.User.Identity.Name is empty at the time Session_Start is called. It worked as expected.

asp.net c# - setting session then redirecting users via global.asax

hello I'm trying so hard for this, I cant understand most question since this is my first time developing in ASP.NET here is my problem.
Im declaring session variable when the user click the submit in the login page then redirecting them to somepage.aspx
if (dt.Rows.Count > 0)
{
Session["usersId"] = usersId;
Session["usersLevel"] = usersLevel;
Session["usersRegion"] = usersRegion;
Session["notification"] = "";
Response.Redirect("pages/Dashboard.aspx");
}
So after that that I put something in my Web.config
<system.web>
<compilation debug="true" targetFramework="4.0"/>
<sessionState timeout = "1" mode = "InProc" />
</system.web>
So ofcourse the session will expire?/timeout? then in my Global.asax I put this
void Session_End(object sender, EventArgs e)
{
Response.Redirect("Login.aspx");
}
However an HttpExeception rises, that says
Response is not available in this context.
Why did the response is not available? when it said that the sessionstate mode must be set to InProc? I just want the user to be redirected in that page when the session expires/timeout(I dont know their difference but looks same to me)
thank you

You may consider to do the redirect in AuthenticateRequest event. Only inProc sessionstate provider supports session end event and it may happen any time(even after the relevant request is responsed, that's why you saw that exception).

How to have and manage the Session Timeout in this simple asp.net webforms application?

I am a new ASP.NET Webforms developer and I am struggling right now with how to have and manage session timeout in my simple test application. Generally speaking, the test application is listing a number of items. The user can add whatever he wants to a shopping cart and when he clicks on Checkout, he will be asked to enter his information. There is no login or authentication. However, I am using session variables to pass the user information between different pages.
I need to have a timeout here in such a case that the user leaves the page for a long time. In this case, he should get a message and gets redirected to the home page or any other page.
How to do that?
I tried to do that by adding the following to the web.config file:
<sessionState
mode="InProc"
stateConnectionString="tcpip=127.0.0.1:42424"
stateNetworkTimeout="60"
sqlConnectionString="data source=127.0.0.1;Integrated Security=SSPI"
cookieless="false"
timeout="60"
/>

I was trying to retrieve thousands of records from a web service according to the input parameters and naturally it was trowing timeout exceptions. I decided to put the following code in action to display a client-side message, so the user would change the input parameters to make the results more specific.
You can find this example in here.
Executes any code block:
public static bool ExecuteWithTimeLimit(TimeSpan timeSpan, Action codeBlock)
{
try
{
Task task = Task.Factory.StartNew(() => codeBlock());
task.Wait(timeSpan);
return task.IsCompleted;
}
catch (AggregateException ae)
{
throw ae.InnerExceptions[0];
}
}
For a specific amount of time:
bool Completed = ExecuteWithTimeLimit(TimeSpan.FromHours(1), () =>
{
/*your code block*/
});
After stopping the execution, you can redirect to the desired page.

First off I'd like to point you to this page here as it seems that:
You are using InProc mode, though providing state server information and timeout which does not make much sense.
There are different modes in this so most probably you only need
mode, timeout and cookieless items for InProc (which is the best choice for test applications)
Have you made sure that this is under system.web in web.config?
<configuration>
<system.web>
<sessionState mode="InProc"
cookieless="false"
timeout="20"/>
</sessionState>
</system.web>
</configuration>
As an extra, your timeout is 60 minutes. Have you waited long enough? If the session is not set anymore you need to handle the redirect yourself.
Here is another SO page that might help you
By the way, if you are to use the in proc mode you can handle session expiry in global.asx
void Session_End(object sender, EventArgs e)
{
// Code that runs when a session ends.
// Note: The Session_End event is raised only when the sessionstate mode
// is set to InProc in the Web.config file. If session mode is set to StateServer
// or SQLServer, the event is not raised.
Response.Redirect("Add url here");
}

Losing session data in ASP.NET

I moved an ASP.NET site running on a server with .NET 1.1 to another server running with .NET 2.0.
In one of the pages I have the following code to detect an expired session:
protected void Page_Init(object sender, System.EventArgs e) {
if ( Session["XBCPEmail"] == null ) {
Response.Redirect("signin.aspx?expired=yes");
return;
}
}
(Session["XBCPEmail"] == null) is resolving as true (as if the session had expired) in one unexpected case, after clicking one of the buttons of the page. It happens with only one of the buttons. Just like other buttons in the same page, the button event handler ends with this code redirecting to the same page:
Response.Redirect("cpanel.aspx");
I checked and at the time of Response.Redirect("cpanel.aspx"); the value of (string)Session["XBCPEmail"] is a valid string, so I'm not sure what can happen between the Response.Redirect and the Page_Init that could be making the Session["XBCPEmail"] become null.
Which could make a Session variable in .NET 2.0 become null? This code does not have that issue in 1.1 and, even in 2.0, it only affects one button on the page.
UPDATE: The issue only occurs if the button event handler calls an external .exe program, with the code below. If this code is commented out, the Session variable is not null. How can the creation of an external process to run a command line program have any impact on if a Session variable is null or not?
private string CallBridge3(string task, string arg1, string arg2, string arg3) {
Process process = new Process();
process.StartInfo.FileName = MapPath("bridgefcp.exe");
process.StartInfo.Arguments = "-" + task + " \"" + arg1 + "\" \"" + arg2 + "\" \"" + arg3 + "\"";
process.StartInfo.RedirectStandardOutput = true;
process.StartInfo.UseShellExecute = false;
process.Start();
string output = process.StandardOutput.ReadToEnd();
process.WaitForExit();
return output;
}
UPDATE 2: The problem has vanished after installing .NET 4.5 on the Windows 2008 R2 with IIS 7.5 machine, instead of using the one that came by default, which was .NET 2.0.

By default Response.Redirect terminates thread execution and there might be a race conditions in setting session variables. It is described in article Don't redirect after setting a Session variable (or do it right), so try to use another, less violent version:
Response.Redirect("cpanel.aspx", false);

Check your web.config, maybe you have this tag
<httpCookies requireSSL="true" />
If it so, remove it.

You need to update web.config as mention below :
<httpCookies requireSSL="false" />

I was facing the same issue and tried every option mentioned in the above answers.
Finally found that the issue was that we had marked session cookie as secure in our project but were running it with http
If the server has not been setup for SSL and you try to mark the cookie secure, a new session will be generated for each request.
So finally enabling back https fixed it for me.

I believe your session in the web.config is being reset (getting a new SessionID for each postback)
You could try to debug this by putting the SessionID somewhere on the page (for testing) with
HttpContext.Current.Session.SessionID
This did happen on one of my websites and all i had to do was go into IIS and resave the SessionState Panel

Just go to your web.config file and edit your sessionstate tag. Set requiressl to false from true.

I encountered this problem when setting the Session variable before a redirect. I had enableSessionState="ReadOnly" in Web.config. It happens because the session does not exists and the redirect happens before the client can set the session cookie.
My solution was to set a dummy Session variable in the previous page load (login page in my case).
protected void Page_Load(object sender, EventArgs e)
{
// Put this in master page or login page
Session["createSession"] = true; /* ensure there's a cookie for session */
}

<httpCookies requireSSL="false" />
Removing this from the local web.config worked for me. The issue was only happening when running the app locally.
Removed the setting from web.config
Added it to the web.staging.config and web.production.config

For MVC, make sure the web.config has below configuration.
<httpCookies httpOnlyCookies="true" requireSSL="false" />
in <system.web> section

Redirecting to another page on Session_end event

I would like to auto-redirect to login page when session time outs.
In web.config file, i have the following code
<configuration>
<system.web>
<sessionState mode="InProc" timeout="1"/>
</system.web>
</configuration>
In Global.asax file-
protected void Session_End(object sender, EventArgs e)
{
Response.Redirect("LoginPage.aspx");
}
But after time-out, i am receiving the following error:
HttpException was unhandled by user code.
Response is not available in this context.
Any clue to solve this issue?

Session_End is called when the session ends - normally 20 minutes after the last request (for example if browser is inactive or closed).
Since there is no request there is also no response.
I would recommend to do redirection in Application_AcquireRequestState if there is no active session. Remember to avoid loops by checking current url.
Edit: I'm no fan of .Nets built in authentication, Example goes in Global.asax:
protected void Application_AcquireRequestState(object sender, EventArgs e)
{
try
{
string lcReqPath = Request.Path.ToLower();
// Session is not stable in AcquireRequestState - Use Current.Session instead.
System.Web.SessionState.HttpSessionState curSession = HttpContext.Current.Session;
// If we do not have a OK Logon (remember Session["LogonOK"] = null; on logout, and set to true on logon.)
// and we are not already on loginpage, redirect.
// note: on missing pages curSession is null, Test this without 'curSession == null || ' and catch exception.
if (lcReqPath != "/loginpage.aspx" &&
(curSession == null || curSession["LogonOK"] == null))
{
// Redirect nicely
Context.Server.ClearError();
Context.Response.AddHeader("Location", "/LoginPage.aspx");
Context.Response.TrySkipIisCustomErrors = true;
Context.Response.StatusCode = (int) System.Net.HttpStatusCode.Redirect;
// End now end the current request so we dont leak.
Context.Response.Output.Close();
Context.Response.End();
return;
}
}
catch (Exception)
{
// todo: handle exceptions nicely!
}
}

If you are using something like FormsAuthentication for maintaining the security of your application, then this part (that part that you are trying to do) will be done for you. If FormsAuthentication discovers that a user's session has expired it will redirect him or her back to you login page.
Second, don't rely too much on Session_End because it will never trigger if you change session provider from InProc to SQLServer or other out of process provider.

You can use session property IsNewSession to detect whether it is session timeout or not.
The ASP.NET HttpSessionState class has IsNewSession() method that returns true if a new session was created for this request. The key to detecting a session timeout is to also look for the ASP.NET_SessionId cookie in the request.
Definitely I too agree that we should put the below code in some so called a custom BasePage, which is used by all pages, to implement this effectively.
override protected void OnInit(EventArgs e)
{
base.OnInit(e);
if (Context.Session != null)
{
if (Session.IsNewSession)
{
string CookieHeader = Request.Headers["Cookie"];
if((CookieHeader!=null) && (CookieHeader.IndexOf("ASP.NET_SessionId") >= 0))
{
// redirect to any page you need to
Response.Redirect("sessionTimeout.aspx");
}
}
}
}
check this link for more explanations if you want to put the above code in a base page class .

You should use Application_AcquireRequestState
You'll find that Application_AuthenticateRequest no longer has a session context (or never had one).
In my research into this I cam across this post which solved it for me.
Thanks go to Waqas Raja.
asp.net: where to put code to redirect users without a session to the homepage?

I think you are getting "Response is not available in this context" because the user is not making a request to the server, and therefor you cannot provide it with a response. Try Server.Transfer instead.

The easiest way what I feel is to use Meta information and get the trick working. Consider we have a page WebPage.aspx add the below code in the the WebPage.aspx.cs file.
private void Page_Load(object sender, System.EventArgs e){
Response.AddHeader("Refresh",Convert.ToString((Session.Timeout * 60) + 5));
if(Session[“IsUserValid”].ToString()==””)
Server.Transfer(“Relogin.aspx”);
}
In the above code, The WebPage.aspx is refreshed after 5 seconds once the Session is expired. And in the page load the session is validated, as the session is no more valid. The page is redirected to the Re-Login page. Every post-back to the server will refresh the session and the same will be updated in the Meta information of the WebPage.aspx.

you can simply do the following in web.config
<configuration>
<system.web>
<sessionState mode="InProc" timeout="1" loginurl="destinationurl"/>
</system.web>
</configuration>
Since, we can't redirect from Session_End as no response/redirect is present there.By using this you will be redirected to destinationurl when session will timeout.Hope this helps.