Authentication Not Working!!!

Hey there,

I have a table [user] in a SQLExpress database [Database.mdf] in the App_Data folder. There are two columns. [userId] and [password]. I want to authenticate the user who wants to log in through a Login control. the user should have his userId and password in the [user] table. I digged and made my code. but it doesn't work it keeps giving me that the user is not authenticated. i guess it has no errors. please tell me if you find the error. here is the code: 1 protected void Login1_Authenticate(object sender, AuthenticateEventArgs e)
2 {
3 SqlConnection conExpress = new SqlConnection("Data Source=.\SQLEXPRESS;Initial Catalog=Database;Integrated Security=True;User Instance=False"); //Create the server connection
4
5 try
6 {
7 string id_user = Login1.UserName.Trim(); //Get the username from the control
8 string pass_user = Login1.Password; //get the Password from the control
9
10 //These are a sql and connection Examples
11 string sql = "SELECT userId, password FROM user WHERE userId = @param_Id AND password = @param_Password";
12 SqlCommand comSQL = new SqlCommand(sql, conExpress); //Create the sql command using sql string and sql connection
13
14 //Add the sql parameters
15 comSQL.Parameters.AddWithValue("@param_Id", id_user); //New on VS 2.0
16 comSQL.Parameters.AddWithValue("@param_Password", pass_user);
17
18 string cod_user = "";
19 string name_user = "";
20
21 //Open database connection
22 conExpress.Open();
23 SqlDataReader dr = comSQL.ExecuteReader();
24 while (dr.Read())
25 {
26 cod_user = dr.GetValue(0).ToString(); //The coduser is unique onto database table
27 name_user = dr.GetValue(1).ToString();
28 }
29 conExpress.Close();//Close Database Connection
30 if (cod_user != "") //The user exist onto database
31 {
32 //Create the session vars
33 Session["coduser"] = cod_user;
34 Session["nameuser"] = name_user;
35 e.Authenticated = true; //Grant the access, Goes to DestinationPageUrl
36 }
37 }
38 catch(Exception)//On Login Error
39 {
40 e.Authenticated = false;//Confirm that you are out
41 conExpress.Close();//On any error case, close the database connection
42 }
43 }