ขอตัวอย่างวิธีการส่งค่าผ่าน URL Patameter หน่อยครับ

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;

public partial class LoginPage : System.Web.UI.Page
{
    String strConn = ConfigurationManager.AppSettings["strConnection"];
    SqlConnection objConn = new SqlConnection();
    DataTable dt = new DataTable();
    ClsDataBase cdb = new ClsDataBase(); // New Object ClsDataBase
    String dbName = "strConnection";
    String err = "";
    String strSQL;

    private void Connection()
    {
        try
        {
            if (objConn.State == ConnectionState.Open)
            {
                cdb.CloseDB(objConn, ref err); // ClsDataBase CloseDB
            }

            strSQL = "select * from LoginTable";
            objConn = cdb.OpenDB(dbName, ref err);
            dt = cdb.Execute2DataTable(strSQL, objConn); // ClsDataBase Execute2DataTable
        }
        catch (Exception ex)
        {
            Response.Write(ex.ToString());
        }
    }

    protected void Page_Load(object sender, EventArgs e)
    {

    }

    protected void Button1_Click1(object sender, EventArgs e)
    {
        try
        {
            strSQL = "SELECT Username, Password, RoleID FROM LoginTable WHERE Username=@Username AND Password=@Password";

            objConn = cdb.OpenDB(dbName, ref err); // ClsDataBase OpenDB

            SqlCommand cmd = new SqlCommand(strSQL, objConn);
            cmd.Parameters.AddWithValue("@Username", txtUsername.Text.Trim());
            cmd.Parameters.AddWithValue("@Password", txtPassword.Text.Trim());
            SqlDataReader dtReader = cmd.ExecuteReader(); // ClsDataBase ExecuteReader

            try
            {
                if (dtReader != null && dtReader.HasRows == true)
                {
                    if (dtReader.Read())
                    {
                        Session["User"] = dtReader["Username"].ToString();
                        Session["Pass"] = dtReader["Password"].ToString();
                        Session.Timeout = 10;
                    }
                    dtReader.Close();
                    Response.Redirect("Index.aspx");
                }
                else
                {
                    Page.ClientScript.RegisterClientScriptBlock(this.GetType(), "CallJs", "alert('Username หรือ Password ไม่ถูกต้อง');", true);
                }
            }
            finally
            {
                objConn.Close();
            }
        }
        catch (Exception ex)
        {
            Response.Write(ex.ToString());
        }
    }

    protected void Button1_Click2(object sender, EventArgs e)
    {
        txtUsername.Text = "";
        txtPassword.Text = "";
    }
}