Session and HttpContext not available in web part

Question

I have a web part in which I have Grid View which displays data from a custom list. In the Page_Load I am initializing the DataTable. I want to store the DataTable object in Session object so that it wont fetch it again and again, similar to what has been done in this example.

Session["data"] = dataTableObject;

But the code shows compile time error.

The name 'Session' does not exist in current context.

I even tried to to use HttpContext from this answer.

HttpContext.Current.Session["data"] = dataTableObject;

But it shows the same error.

Answer 1

in your webpart you need to change the web.config:

<pages enableSessionState="false" enableViewState="true" enableViewStateMac="true" validateRequest="false" pageParserFilterType="Microsoft.SharePoint.ApplicationRuntime.SPPageParserFilter, Microsoft.SharePoint, Version=14.0.0.0, Culture=neutral, PublicKeyToken=*******" asyncTimeout="7">

to

<pages enableSessionState="true" enableViewState="true" enableViewStateMac="true" validateRequest="false" pageParserFilterType="Microsoft.SharePoint.ApplicationRuntime.SPPageParserFilter, Microsoft.SharePoint, Version=14.0.0.0, Culture=neutral, PublicKeyToken=*******" asyncTimeout="7">

and also add this in:

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

the above goes within:

<modules runAllManagedModulesForAllRequests="true">

so you need to find the modules tag and add it in, it will look somthing like this:

<modules runAllManagedModulesForAllRequests="true">
  <remove name="Session" />
  <add name="Session" type="System.Web.SessionState.SessionStateModule" preCondition="" />
</modules>

then within your webpart you can do:

to save string:

Page.Session["storethis"] = "hello world";

to get string:

string helloWorld = Page.Session["storethis"].ToString();

also how is your class made? are you inheriting from the webpart class? im asking becasue this error is shown when you dont inheirt from a class (webpart or page) or not set within web.config

as an example this is my redirect class webpart that redirects when on a page that is loaded, it gets the session value that im soring (url) and redirecting:

public class httpRedirectHome : WebPart
{
    protected override void CreateChildControls()
    {
    }

    protected override void OnInit(EventArgs e)
    {

        changeRedirection(Page.Session["PreviousPageUrl"].ToString());


        base.OnInit(e);
    }

    private void changeRedirection(string url)//,string extentionType)
    {
        if (Page.Session["PreviousPageUrl"] != null)
        {
            Page.Response.Redirect(url);
        }
    }
}

as you can see its a webpart that iv made (public) and im inheriting from webpart class

public class httpRedirectHome : WebPart

if it was an aspx.cs it would be somthing like:

public partial class showBifDetails : System.Web.UI.Page

http://msdn.microsoft.com/en-us/library/system.web.httpcontext.session(v=vs.110).aspx

Answer 2

You'd need to enable Session State in your web application.

1. Execute the following powershell script Enable-SPSessionStateService –DefaultProvision

2. Apply the following web.config change:

   pages enableSessionState="true"
   

More information is available at: Using Session State in SharePoint 2010

Answer 3

For me I just needed to run this PowerShell Command and it works

Enable-SPSessionStateService -DefaultProvision

After this, the following works

HttpContext.Current.Session["toto"] = "toto";