Establishing SQL Connection for Login Page

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.Sql;

using System.Data.SqlClient;

namespace WebApplication1

{

    public partial class _Default : System.Web.UI.Page

    {

        protected void Page_Load(object sender, EventArgs e)

        {

        }

        protected void Button3_Click(object sender, EventArgs e)

        {

 SqlConnection con = new SqlConnection (@"Data Source=server name;Initial Catalog=database name;Trusted_Connection=true");

          

            SqlCommand cmd = new SqlCommand("SELECT Username,Password from tablename where Username='" + TextBox1.Text + "' and  Password='" + TextBox2.Text + "'",con);

            con.Open();

           

            SqlDataReader dr = cmd.ExecuteReader();

           

           if(dr.Read())

            {

                Response.Redirect("HomePage.aspx");//Mention the page which you want to link when logged in

                Response.Write("LoggedIn Successfully");

            }

            else

            {

                Response.Write("LogIn Failed");

            }

           con.Close();

       

        }

       }}