How to strone login user session id in database table?

Question

protected void TextBox2_Click(object sender, EventArgs e)

{

using (SuperFastEntities db = new SuperFastEntities())

{

sample u = new sample();

u.name = sname.Text;

string id = Session["username"].ToString().Trim();

u.userID =Convert.ToInt32(id);

db.samples.Add(u);

db.SaveChanges();

}

 

Here is my code but not successfull. can somone help please!!