How to create connection Ado.net and SqlServer 2008

<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="Registration.aspx.cs" Inherits="Login_and_signup.Registration" %>





   


   

   

   
           
               
           
           
               
               
           
           
               
               
           
           
               
               
           
           
           
               
               
           
           
               
               
           
           
               
           
           
           
           
       

User Registration Form
First Name:
Last Name:
Username:
Password:
Address:
onclick="btnSubmit_Click" />                          Text="Reset" onclick="btnReset_Click" />

   

   

using System;
using System.Collections;
using System.Configuration;
using System.Data;
using System.Linq;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Xml.Linq;
using System.Data.SqlClient;
namespace Login_and_signup
{
    public partial class Registration : System.Web.UI.Page
    {
     
        protected void btnSubmit_Click(object sender, EventArgs e)
        {
            string connStr = ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString;
            SqlConnection sqlConnection = new SqlConnection(connStr);
            //sqlConnection.ConnectionString = @"Data Source=SS438\SQLEXPRESS;Initial Catalog=Examples;Integrated Security=true;";
            sqlConnection.Open();
            string sqlQuery = "INSERT INTO Users(FirstName,LastName,UserName,Password,Address) VALUES(@FirstName,@LastName,@UserName,@Password,@Address)";
            SqlCommand sqlCommand = new SqlCommand(sqlQuery, sqlConnection);
            sqlCommand.CommandType = CommandType.Text;
            sqlCommand.Parameters.Add("@FirstName", SqlDbType.VarChar).Value = txtFirstName.Text.Trim();
            sqlCommand.Parameters.Add("@LastName", SqlDbType.VarChar).Value = txtLastName.Text.Trim();
            sqlCommand.Parameters.Add("@UserName", SqlDbType.VarChar).Value = txtUserName.Text.Trim();
            sqlCommand.Parameters.Add("@Password", SqlDbType.VarChar).Value = txtPassword.Text.Trim();
            sqlCommand.Parameters.Add("@Address", SqlDbType.VarChar).Value = txtAddress.Text.Trim();
            int irows = sqlCommand.ExecuteNonQuery();
            lblMessage.Text = "User inserted successfully...";
            ClearFields();
        }

        protected void btnReset_Click(object sender, EventArgs e)
        {
            ClearFields();
        }
        private void ClearFields()
        {
            txtFirstName.Text = "";
            txtLastName.Text = "";
            txtUserName.Text = "";
            txtPassword.Text = "";
            txtAddress.Text = "";
        }
    }
}