how can i set session expire time in asp.net(C#)

<configuration>
<system.web>
<sessionstate
mode="InProc"
cookieless="true"
timeout="30" />
</sessionstate></system.web>
</configuration>

<authentication mode="Forms">
  <forms loginUrl="~/Account/Login" timeout="30" slidingExpiration="true" />
</authentication>
<sessionState timeout="30"></sessionState>

</system.web>

By
http://www.code-sample.com/2014/06/distinct-values-from-list-using-linq.html[^]

Try:

Session.Timeout = 15;