Object reference not set to an instance of an object for asp.net

Question

    protected void Page_Load(object sender, EventArgs e)
    {
        lb_msg2.Text = "Hello " + Session["userid"].ToString() + "!";
    }
    protected void Button1_Click(object sender, EventArgs e)
    {

        SqlConnection con = new SqlConnection();
        con.ConnectionString = ConfigurationManager.ConnectionStrings["ProfileCS"].ConnectionString;

        string sql = "Select password from Profile where userid = '" + Session["userid"] + "'";
        SqlCommand cmd = new SqlCommand();
        SqlDataReader dr; // to hold reference of datareader  returned

        //prepare  a place - datatable to hold the data
        DataTable dt = new DataTable();

        //setting up command
        cmd.CommandText = sql;
        cmd.Connection = con;

        //connection and execute command
        con.Open();
        dr = cmd.ExecuteReader();

        dt.Load(dr); // copy data from datareader to datatable

        string pwdcheck;
        pwdcheck = dt.Rows[0]["password"].ToString();

        if (tb_verify.Text.Equals(pwdcheck))
        {
            string password = tb_pwd.Text;

            sql = "Update Profile set password ='" + password + "'";
            sql = sql + "where userid = '" + Session["userid"] + "'";

            cmd.CommandText = sql;
            cmd.Connection = con;

            try
            {
                cmd.ExecuteNonQuery();
                lb_msg.Text = "Password changed succesfully";
            }
            catch (Exception ex)
            {
                lb_msg.Text = "Problems encountered " + ex.Message;
            }


            finally
            {
                con.Close();
                con.Dispose();
                cmd.Dispose();
            }
        }
        else
            lb_msg.Text = "Old password Incorrect";
    }

    protected void lblClick(object sender, EventArgs e)
    {
        FormsAuthentication.SignOut();
        Session.Clear();  // This may not be needed -- but can't hurt
        Session.Abandon();
        FormsAuthentication.RedirectToLoginPage();
    }
}

lb_msg2.Text = "Hello " + Session["userid"].ToString() + "!";

there is an error at the line above with Object reference not set to an instance of an object the change password feature was working before.

Are you sure that your ´Session["userid"]´is not ´NULL´? — Benjamin, Jan 07 '14 at 07:13
possible duplicate of [What is a NullReferenceException and how do I fix it?](http://stackoverflow.com/questions/4660142/what-is-a-nullreferenceexception-and-how-do-i-fix-it) — nvoigt, Jan 07 '14 at 07:14

score 1 · Answer 1 · answered Jan 07 '14 at 07:13

1

In your case Session["userid"] must be NULL,handle it

answered Jan 07 '14 at 07:13

Cris

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yo what does that mean leave it as null in my database – sherrez Jan 07 '14 at 07:18
your session must have expired so value of Session["userid"] is null,thats why you are getting error at Session["userid"].ToString() – Cris Jan 07 '14 at 07:20

Object reference not set to an instance of an object for asp.net

1 Answers1