How to retrieve Session value from JavaScript

[Herman Gouw]

Hi,
In my current project, I am using Visual Studio 2008, .NET Framework 3.5 and Telerik 2011 Q1.
On one of the web pages which use a common master page, I need to retrieve the value of a Session whose is set by the code behind.

<asp:Content ID="Content1" ContentPlaceHolderID="Main" runat="server">
    <script type="text/javascript">
        function showConfirm() {
            var exist = '<%= Session("SubscriptionsExist")%>';
            ...
        }
    </script>
    ...
</asp:Content>

I got the following error message
Compiler Error Message: CS0103: The name 'Session' does not exist in the current context

If I used the following instead
var exist = '<%= Session("SubscriptionsExist")%>';
I got the following error message
Compiler Error Message: CS1955: Non-invocable member 'System.Web.HttpContext.Session' cannot be used like a method.

Can you please help me?

Regards,
Herman

[Shinu]

Hello Herman,

I was not able to create the same error and one suggestion is to save the session variable in a Hidden Field and access it.

//Code Behind
session["name"]="well";
hiddenctrl.value=session["name"].ToString();

client-side:

javascript:
var sessionvalue= document.getElementById('hiddenctrl').value;

Thanks,
Shinu.

[Herman Gouw]

Thanks for the prompt reply.

Is it possible to read the Session value directly from JavaScript without using a hidden control?

The problem with a hidden control is that it is possible to check the value by viewing the source from the browser.

Regards,
Herman

[Shinu]

Hello Herman,
I have made some changes in your code. Please give a try with this.
Javascript:

<script type="text/javascript">
      function accessSession()
      {
          var mySessionVar ='<%=Session["name"]%>';//make sure that you have defined the session variable
          alert(mySessionVar);
      }
  </script>

Thanks,
Shinu.

[Herman Gouw]

Hi Shinu,

I have modified the code to the sample that you gave me.

I have also initialized the Session variable to a value in Global.asax.cs as follows:
        protected void Session_Start(object sender, EventArgs e)
        {
            Session["name"] = true;
        }

However I got the following error message:

The Controls collection cannot be modified because the control contains code blocks (i.e. <% ... %>).

Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.Web.HttpException: The Controls collection cannot be modified because the control contains code blocks (i.e. <% ... %>).

Regards,
Herman

[Veli]

You cannot send a server value (in this case - a session value) to the client and use that in javascript without sending it somewhere in the server response. You need to send that value in your rendered HTML, which is effectively the same as using a hidden field.

Veli
the Telerik team

[Bojjaiah]

Hi thanks for your post sejjestion
now working fine
tahnks alot!