Asp.net read data from database

<pre>using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.Mvc.RazorPages;
using System.Data.SqlClient;

namespace MyStore.Pages.Porezi
{
    public class IndexModel : PageModel
    {
        public List<ClientInfo> listClients = new List<ClientInfo>();
        public void OnGet()
        {
            try
            {
                String connectionString = "Data Source=.\\SQLEXPRESS;Initial Catalog=test;Integrated Security=True;Trust Server Certificate=True";

                using (SqlConnection connection = new SqlConnection(connectionString))
                {
                    connection.Open();
                    String sql = "SELECT * FROM porezi";

                    using (SqlCommand command = new SqlCommand(sql, connection))
                    {
                        using (SqlDataReader reader = command.ExecuteReader())
                        {
                            while (reader.Read())
                            {
                                ClientInfo clientInfo = new ClientInfo();
                                clientInfo.id = "" + reader.GetInt32(0);
                                clientInfo.redni_broj = reader.GetString(1);
                                clientInfo.naziv = reader.GetString(2);
                                clientInfo.procenat= "" + reader.GetString(3);
                                clientInfo.fiksna_vrednost = "" + reader.GetString(4);
                                clientInfo.oznaka = reader.GetString(5);

                                listClients.Add(clientInfo);
                            }
                        }

                    }
                }

            }
            catch (Exception ex)
            {
                Console.WriteLine("Exception: " + ex.ToString());  
            }
        }

        public class ClientInfo
        {
            public String id;
            public String redni_broj;
            public String naziv;
            public String procenat;
            public String fiksna_vrednost;
            public String oznaka;
        }
    }

}

<pre>@page
@model MyStore.Pages.Porezi.IndexModel
@{
}
<br>
<h2>List of Clients</h2>
<a class='btn btn-primary btn-sm' href='/Porezi/Create'>New Client </a>
<table class="table">

    <thead>
        <tr>
            <th>id</th>
            <th>redni_broj</th>
            <th>naziv</th>
            <th>procenat</th>
            <th>fiksna_vrednost</th>
            <th>oznaka</th>
            <th>Action</th>
        </tr>

    </thead>
    <tbody>
        @foreach(var item in Model.listClients)
        {
            <tr>
                <td>@item.id</td>
                <td>@item.redni_broj</td>
                <td>@item.naziv</td>
                <td>@item.procenat</td>
                <td>@item.fiksna_vrednost</td>
                <td>@item.oznaka</td>
                <td>
                    <a class="btn btn-primary btn-sm" href="/Porezi/Edit?id=@item.id">Edit</a>
                    <a class="btn btn-danger btn-sm" href="/Porezi/Delete?id=@item.id">Delete</a>
                </td>

            </tr>
        }
    </tbody>
</table>