Enable SessionState Issue in ASP.NET and Sharepoint 2010

Question

I've been struggling for a week now, I can't find a solution for my problem. I'm fairly new to Sharepoint and want to create a simple webpart.

For this, I need a Session where I can store my DataTable, which contains data from a database.

E.g.:

private void storeDataTable(DataTable dt)
{
    Session["dtSession"] = dt;
}

When I'm debugging this code, an exception is thrown:

Session state can only be used when enableSessionState is set to true, either in a 
configuration file or in the Page directive. Please also make sure that      
System.Web.SessionStateModule or a custom session state module is included in the 
<configuration>\<system.web>\<httpModules> section in the application configuration

What I've done so far, to solve this issue:

Tried to enable SessionState in my ascx.cs - markup

<%@ Control Language="C#" AutoEventWireup="true"  
CodeBehind="MyWebPart.ascx.cs"      
Inherits="MyWebPart.VisualWebPart.VisualWebPartUserControl" %>
<%@ Page EnableSessionState="true" %>

When I am running this, I got an exception:

server tag is not well formed.

Add following to the web.config under "C:\inetpub\wwwroot\wss\VirtualDirectories\80\web.config"
```
<pages enableSessionState="true" enableViewState="true" enableViewStateMac="true">
```
and
```
<httpModules>
    <add name="Session" type="System.Web.SessionState.SessionStateModule" />
</httpModules>
```
3.Run the following in the SharePoint 2010 Management Shell:
```
Enable-SPSessionStateService –DefaultProvision
```
4.Activate the ASP.NET State service under services.msc and change start to automatic.

None of this steps could resolve my issue.

did you check this : msdn.microsoft.com/en-us/library/ms178586.aspx ? — Sebastien H.
No, but as far as I know, I only need the In-Proc-Mode, which is default? I've followed this guide to enable SessionState: nikpatel.net/2012/02/12/… — user2508738
InProc mode will only work i you have a single WFE or if you have persistence configured on your load balancer. Limiting yourself to it is a poor design decision if there is any chance your application could need to scale past one server. — Brian P
Thanks for your reply, but I have to ask: Is the InProc mode the reason, why the SessionState couldn't be enabled? What if there isn't any chance my application need further server resources? — user2508738
no, the inProc mode is the default mode and usualy doesn't create any problem. but, is your webpart integrated inside an other control ? — Sebastien H.

user2508738 user2508738 · Accepted Answer · 2014-02-05T13:52:28

I was able to solve my issue myself. I've searched through both of the web.configs (VirtualDirectories\80 and VirtualDirectories\7099) and deleted some entrys. Now I got the following entries in my web.config:

<httpModules>
     <remove name="Session" />
     <add name="Session" type="System.Web.SessionState.SessionStateModule" />
</httpModules>

and

 <pages enableSessionState="true" enableViewState="true" enableViewStateMac="true" enableEventValidation="true" etc...>

I guess my fault was to have another SessionState declared which was costum. I've deleted these entries and the application works like a charm. So it seems, the exception will also be thrown, when there are to many Sessions declared.

Enable SessionState Issue in ASP.NET and Sharepoint 2010

1 Answers