Login Code Not Working

Below is how I would do it

using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Data.OleDb;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace WindowsFormsApplication1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }
        
        private void button1_Click(object sender, EventArgs e)
        {
            try
            {
                OleDbCommand comm = new OleDbCommand();
                comm.CommandText = "SELECT COUNT(*)  FROM Accounts WHERE username = '@username' and passcode = '@passcode';";
                comm.Parameters.Add("@username", OleDbType.VarChar);
                comm.Parameters.Add("@passcode", OleDbType.VarChar);

                comm.Parameters["@username"].Value = txtUsername.Text;
                comm.Parameters["@passcode"].Value = txtPasscode.Text;
                    
                OleDbDataReader reader = comm.ExecuteReader();

                while(reader.Read())

                {
                    this.Frame.Navigate(typeof(HomeStudent));
                }
            }

            catch
            {

            }

        }
    }
}