Not Comparing the values from the database

Thanks Niradhip, now its working.

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

namespace AirLine
{
    public partial class _Default : System.Web.UI.Page
    {

        
        
        protected void Page_Load(object sender, EventArgs e)
        {
           
        }

        protected void TextBox1_TextChanged(object sender, EventArgs e)
        {
            
        }

        protected void Button1_Click(object sender, EventArgs e)
        {
            generatedata();
           
        }
        
        private void generatedata()
        {
            bool blnFound = false;
            //string username, password;
            //username = TextBox1.Text.Trim();
            //password = TextBox2.Text.Trim();

            SqlConnection conn;
            conn = new SqlConnection("server=HOME-1E79531B32;database=AirLineReservation;trusted_connection=yes");
            conn.Open();
            SqlCommand cmd = new SqlCommand("SELECT * FROM Logon", conn);
            //SelectCommand = "SELECT [UserName], [Password] FROM [Logon] WHERE [UserName] = ";
           // SqlDataAdapter dad = new SqlDataAdapter(cmd);
            //DataSet ds = new DataSet();
//            int das;
            int count = 0;
                
            //dad.Fill(ds);
            SqlDataReader dr = cmd.ExecuteReader();
            while (dr.Read())

            {
                count++;

                if (dr["username"].ToString() == TextBox1.Text)
                {
                    if (dr["password"].ToString() == TextBox2.Text)
                    {
                        blnFound = true;
                        Server.Transfer("SuccessfullLogin.aspx");
                    }
                }
            }
            if (!blnFound)
                Label4.Text = "Invalid User or Password";
            TextBox1.Text = "";
            TextBox2.Text = "";
            dr.Close();
            conn.Close();
            
            //DataTable dr = ds.Tables[0];
            //for (int i = 0; i < dr.Rows.Count; i++)
            //{
            //    string username1 = dr.Rows[i][0].ToString();
            //    string password1 = dr.Rows[i][1].ToString();
            //    //int stat = Convert.ToInt32(dr.Rows[i]["status"]);
            //   if ((username1 == username) && (password1 == password))
            //        {
            //            Server.Transfer("SuccessfullLogin.aspx");
            //            break;
            //        }
            //        else
            //        {
            //            Server.Transfer("Register.aspx");
            //        }
                
               
            //}

                
        }

        protected void Button2_Click(object sender, EventArgs e)
        {
            Response.Redirect("Register.aspx");
        }
    }
}
/////////////////////////////////////////
It's only comparing the first value of username and password from the database. but when i try to put other username and password it throws error invalid username and password.

The string from the text box and string form the database are same but it does not throws to successfullLogin page it goes in else.

What is the specific problem in the code and what do you want to achieve exactly? THanks.