Code for Logout in aspx.cs file

protected void logout_OnClick(object sender, EventArgs e)
{
Session.Abandon();Response.Redirect("login.aspx");
}protected void Page_Init(object sender, EventArgs e)
{
Response.Cache.SetExpires(DateTime.UtcNow.AddMinutes(-1));Response.Cache.SetCacheability(HttpCacheability.NoCache);
Response.Cache.SetNoStore();
}