extend session time out for asp.net (step by step!!) - asp.net

Question

I am using session value to identify the language that user chosen.
LoadMultilingual() is the method that I will call for all pages to assign the value for label.
I realized that the session value wont store value for long time, by default it store 20 minutes, so when user click any button that will reload the multilingual function, it will prompt an error.
I set the time out for session value for 60 minutes, when I try to click a button at around 45 minutes, it throw me this value.
the code below is how I declare the timeout for session
<sessionState
mode="InProc"
cookieless="true"
timeout="60" />
The code below is the code form C# that user choose their preferred language at Login page..
protected void Page_Load(object sender, EventArgs e)
{
Session["index"] = null;
Session["counter"] = null;
Session["LoginMsg"] = null;
if (Session["Lang"] == null)
{
Session["Lang"] = Request.UserLanguages[0];
}
if (Session["login"] == null)
{
Session["login"] = 1;
}
if (!IsPostBack)
{
LoadMultilingual();
if ((String)Session["Lang"] == "zh-TW")
{
ddLang.SelectedIndex = 1;
}
else
{
ddLang.SelectedIndex = 0;
}
}
Session["stop"] = null;
}
protected void ddLang_SelectedIndexChanged(object sender, EventArgs e)
{
Session["Lang"] = ddLang.SelectedValue;
LoadMultilingual();
}
The code below is the code from C# that use session for multilingual.
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
DisableLinkBtn();
LoadMultilingual();
}
}
private void LoadMultilingual()
{
Thread.CurrentThread.CurrentCulture = new CultureInfo(Session["Lang"].ToString());
rm = new ResourceManager("SOMaintenance.App_GlobalResources.Lang", Assembly.GetExecutingAssembly());
ci = Thread.CurrentThread.CurrentCulture;
Site1 site = this.Master as Site1;
if (site != null)
{
Label SensorTemperatureLabel = site.FindControl("label1") as Label;
string header = validate.getError("userheader", (String)Session["Lang"]);
SensorTemperatureLabel.Text = header;
}
if ((String)Session["Lang"] == "zh-TW")
{
GridView1.Columns[0].HeaderText = "用户账号";
GridView1.Columns[1].HeaderText = "用户名称";
GridView1.Columns[2].HeaderText = "用户职位";
}
btnAdd.Attributes.Add("title", rm.GetString("btnAdd", ci));
btnSearch.Attributes.Add("title", rm.GetString("btnSearch", ci));
}
Anyone has any idea why it is not working? my code work perfectly find within 40 minutes, the things is I already set the session timeout for 60 minutes.
The error is pointing to session["Lang"] this value. (its only appear around 45 minutes and after, I tried on 25minutes it's ok)

Answer 1

If someone visits the page before you've initialize Session["Lang"] then they'll get a null reference exception. So you need to initialize it. The best place to do that is in the Session_Start event in your global application class (global.asax).
protected void Session_Start(object sender, EventArgs e)
{
Session["Lang"] = //add your code here to figure out the language
}
By initializing it in the session start, you can ensure the variable will always be initialized (unless you later set it to null).
Also, you have cookieless authentication enabled. Do not do that! That's very insecure, as sensitive data will now be stored in the URL..

Answer 2

After tested all the method for THREE days. I have found out the solution.
For those which to extend Session in asp.net can use this method.
Step 1 - set session time out at web.config
Copy and paste the code below to web.config
<authentication mode="Forms">
<forms timeout="60"/>
</authentication>
<sessionState
mode="InProc"
cookieless="true"
timeout="60" />
Please take note, by default session value only last for 20 minutes, as code above, I have set it to 60 minutes.
Step 2 - configuration IIS
If you publish your web application to IIS, go to IIS Manager.
Start --> IIS Manager --> Sites --> Default Web site --> ASP
(If you didnt create a new one for your web app, else just click on the one you use for your web app)
then find Session Properties --> time-out set it to 01:00:00 it means 60 minutes.
By default you should see 00:20:00
After that click Apply on your right hand side.
Sample screen as below
After you done the step above, u can laugh your web application, then problem SOLVED!!!
Have a nice day and hope it help!