How to remove the "user specific data-cache" once the session(In Proc) gets timeout in ASP.Net?

Question

We are setting session-timeout for 1 hour:

<system.web>  
  <sessionState mode="InProc" timeout="60"/>  
</system.web> 

It works as expected.

Alongwith "Session", we create user specific data-cache to reuse the data.

We use unique cache-key for each logged in user:

var studentId = GetStudentIdFromRequest();
var cacheKey = "SyllabusInfoCacheKey_" + studentId;

We set the expiration time of cache as:

Cache.Insert("MyKey", myObject, null, DateTime.Today.AddDays(1), TimeSpan.Zero);

But I need to remove the user specific data-cache once the session gets timeout.

Kindly help me out.

Answer 1

Please try below.

Put below code in Global.asax file in your project.

Shared Dict As New Dictionary(Of String, String)

Sub Application_Start(ByVal sender As Object, ByVal e As EventArgs)
    ' Code that runs on application startup
    Application.Add("AllSession", Dict)
End Sub

Sub Session_End(ByVal sender As Object, ByVal e As EventArgs)
    ' 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.
    If Dict.ContainsKey(Me.Session.SessionID) Then
        HttpRuntime.Cache.Remove(Dict.Item(Me.Session.SessionID))
        Dict.Remove(Me.Session.SessionID)
        Application.Add("AllSession", Dict)
    End If
End Sub

Please put this code in you vb file where you are assigning session.

    Dim cacheKey As New Random
    Dim DictcacheKey As Dictionary(Of String, String)

    DictcacheKey = Application("AllSession")
    If Not DictcacheKey.ContainsKey(HttpContext.Current.Session.SessionID) Then
        DictcacheKey.Add(HttpContext.Current.Session.SessionID, cacheKey.Next())
        Application.Add("AllSession", DictcacheKey)
        Cache.Insert(cacheKey.Next(), DictcacheKey, Nothing, DateTime.Today.AddDays(1), TimeSpan.Zero)
    End If

Note: convert this code in C# if you are not using vb.