1.(It looks like this way is much priority to other ways)
IIS 里面有个设置 站点属性-》主目录-》应用程序配置-》选项-》启用会话状态-》会话超时,可以设置
2.Session.Timeout
3.web.config设置sessionState
在web.config里面设置
<sessionState mode="InProc" stateConnectionString="tcpip=127.0.0.1:42424" sqlConnectionString="data source=127.0.0.1;Trusted_Connection=yes" cookieless="false" timeout="20"/>
timeout的值设成你想要的就可以了