关于登陆界面连接数据库的问题

我做了一个登陆界面，大概就是下面的这样：
  用户名：
  密码：
  登录    取消
还有用sql数据库建立了一个表，login.mdf，怎么才能把两者连接起来？
很急，在线等！ --------------------编程问答-------------------- 看书....... --------------------编程问答-------------------- //using System.Data;
//using System.Data.SqlClient;
using (SqlConnection cn = new SqlConnection(%%1))
//ConfigurationManager.ConnectionStrings["db2ConnectionString"].ConnectionString
//Data Source=myServerAddress;Initial Catalog=myDataBase;User Id=myUsername;Password=myPassword;
      {
          SqlCommand cmd = new SqlCommand("Select Count(*) From jobs",cn);
          cn.Open();
%%2=cmd.ExecuteScalar(); //Message.InnerHtml
if(%%2==%%3)
{
%%4
}

--------------------编程问答-------------------- 这个问题问的。。。
1，配置链接字符串
2，使用ado.net进行数据库的操作
3，根据操作结果来执行逻辑 --------------------编程问答--------------------   protected void Button1_Click(object sender, EventArgs e)
    {
        SqlConnection conn = new SqlConnection();
        conn.ConnectionString = "Data Source=.\\SQLEXPRESS;Integrated Security=True;Connect Timeout=30;User Instance=True;AttachDbFilename=" + Server.MapPath("\\***\\App_Data\\login.mdf");//你数据库的地址
        conn.Open();
        SqlCommand cmd = new SqlCommand();
        string username = this.username.Text;
        string pwd = this.password.Text;
        cmd.CommandText = "select * from tbuser where username='" + username + "'and password='" + pwd + "'";
        cmd.Connection = conn;
        SqlDataReader sdr = cmd.ExecuteReader();
        if (sdr.Read())
        {
            Session["username"] = username;
            sdr.Close();
            conn.Close();
            Response.Write("<script>alert('恭喜你,登陆成功！');window.location.href='news/Default.aspx';</script>");
        }
        else
        {
            sdr.Close();
            conn.Close();
            Response.Write("<script>alert('登陆失败，请确认您的用户名和密码！');window.location=window.location;</script>");
            //Response.Write("用户名或密码错误！");
            //Response.Redirect("login.aspx");
        }
    }
    protected void Button2_Click(object sender, EventArgs e)
    {
        this.username.Text = "";
        this.password.Text = "";
    }

补充：.NET技术 ,  C#