SessionID changing between postbacks

wlangel · September 7th, 2006, 11:17 AM

In my code, I have noticed that the SessionID is being changed as I move from page to page in the same browser. I duplicated this with a single form.

Add this to the form
<asp:TextBox ID="TextBox1" runat="server"></asp:TextBox>
<asp:Button ID="Button1" runat="server" Text="Button" />

In the Page_Load add
TextBox1.Text = Session.SessionID.ToString();

As you click the Button, the SessionID changes. Why? I thought the SessionID was to be the same for the browser session?

RobC · September 20th, 2006, 11:23 AM

If you do a Google search, you'll see that there are several possible reasons for this. One possible reason is that you have to add at least one item to the Session object before either jumping to another page or before refreshing the current page.

For example:

Code:

protected void Page_Load(object sender, EventArgs e)
{
  if (Session["test"] == null) Session.Add("test", "yo");
  TextBox1.Text = Session.SessionID.ToString();
}

If you comment out the "if" statement above, you'll see a different SessionID every time you refresh the page.