Creation of a web form for user login in ASP.NET

Question

I'm trying to solve this problem: I would like to associate an authentication page (login) to a database. I can't figure out how to use the connection string...

Practically, in the C # code behind the button created in ASP, I wrote the following code:

using (SqlConnection connection = new SqlConnection("server=(LocalDB); database=DBProva;")) 

{ 

 connection.Open(); 

} 

I was suggested to configure the connection also in the Web.config, but nevertheless it gives me an error on the line Connection.Open ();

Answer 1

it was my old education code u should try maybe

using System;
using System.Collections.Generic;
using System.Data.SqlClient;
using System.Linq;
using System.Web;
using System.Web.Configuration;
using System.Web.UI;
using System.Web.UI.WebControls;

public partial class Uye_UyeLogin : System.Web.UI.Page
{
 SqlConnection baglanti = new 
 SqlConnection(WebConfigurationManager.ConnectionStrings["LocalDbYemekSiparis"].ConnectionString);

protected void Page_Load(object sender, EventArgs e)
{

}
protected void FormView1_ItemInserted(object sender, FormViewInsertedEventArgs e)
{
    Label1.Text = "Kaydınız başarıyla gerçekleşmiştir.";
}

protected void Button1_Click(object sender, EventArgs e)
{
    // Üye Girişi
    string sql = "SELECT * FROM Tbl_Musteriler where TcKimlik=@tc and MusteriSifre=HASHBYTES('MD5',@Sif)";
    SqlCommand komut = new SqlCommand();
    komut.CommandText = sql;
    komut.Connection = baglanti;
    komut.Parameters.AddWithValue("@Tc", TextBox1.Text);
    komut.Parameters.AddWithValue("@Sif", TextBox2.Text);
    baglanti.Open();
    SqlDataReader satir = komut.ExecuteReader();
    if (satir.Read())
    {
        Session["KullaniciTipi"] = "Musteri";
        Session["KullaniciId"] = (int)satir["MusteriId"];
        Session["OturumTc"] = satir["TcKimlik"].ToString();
        Session.Timeout = 120; // Oturum süresi dk
        Response.Redirect("/Uye/UyeDefault.aspx");
    }
    else
    {
        Label2.Text = "Hatalı Giriş.";
    }
}

}

Answer 2

Try declaring a Myconn string in your global.asax such as the following

public static string MyConn= ConfigurationManager.ConnectionStrings["myConnectionString"].ConnectionString;

and when you need it in your Code just call

SqlConnection con = new SqlConnection(Global.MyConn);

and Most important don't forget to declare a connection string that corresponds your database in your Web.Config ex:

<connectionStrings>
    <add name="myConnectionString" connectionString="Data Source=(local);Initial Catalog=DBNAME;Integrated Security=True" />
</connectionStrings>