Question

just trying to learn asp.net
i am able to login and redirect to default.aspx.
i am trying to check if user’s usere name and password are right from database(able to do).
now i am trying to store user name in session(not able to do, here i am getting nullpointer/value error) and show this session value as welcome message on next page/redirected page.my code is as:

protected void Button1_Click(object sender, EventArgs e)
{
    SqlDataReader dr;
    SqlConnection con = new SqlConnection("Data Source=xxxx-pc\\ddd;Initial Catalog=db_Login;User Id=sd;Password=ds;");
    con.Open();
    SqlCommand com = new SqlCommand("select password from tab_userinformation where Username='" + txt_uname.Text + "'", con);
    dr = com.ExecuteReader();
    if (dr.HasRows)
    {
        dr.Read();

        if (dr[0].ToString() == txt_pwd.Text)
        {
            Response.Redirect("default_Page.aspx");
            //Response.Redirect("erp.htm");
            Session["user"] = txt_uname.Text;

here i am getting object reference not set to an instance of an object exception for Session[“user”]

any suggestion
Thanks!

Answer 1

Store the value in your Session before the Redirect:

Session["user"] = txt_uname.Text;
Response.Redirect("default_Page.aspx");

That way you don’t lose the value of txtuname.Text.

Also, you should use parameterized queries for your SQL – the way you currently have it, you are open to SQL Injection Attacks.