Question

static List<string> keywordList = new List<string>();

protected void btnEnter_Click(object sender, EventArgs e)
{
    lbxKeywords.Items.Add(tbxKeyword.Text);
    keywordList.Add(tbxKeyword.Text);
    tbxKeyword.Text = string.Empty;
}

protected void btnSearch_Click(object sender, EventArgs e)
{
    Session["keywords"] = keywordList;
    keywordList.Clear();
    Response.Redirect("Results.aspx");
}

When I clear the list session become null. why is that?

thanx..

Answer 1

That’s because what you store in the session variable is just a reference to the list, not a copy of the list.

Create a copy of the list for the session variable:

Session["keywords"] = new List<string>(keywordList);