Simple data reading from the database in ASP.NET Webforms.

CatRepository.cs

using System;
using System.Collections.Generic;
using System.Data.SqlClient;

public class CatRepository
{
    private readonly string _connectionString;

    public CatRepository() 
        : base(ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString) { }

    public CatRepository(string connectionString) 
    {
        _connectionString = connectionString;
    }

    public List<Cat> GetCats() 
    {
        var connection = new SqlConnection(_connectionString);
        var cats = new List<Cat>();

        try 
        {
            connection.Open();
            var sql = new SqlCommand("Select [Id], [Name] From [Cats] Order by [Name];", connection);
            var reader = sql.ExecuteReader();

            while (reader.Read())
            {
                var cat = new Cat() 
                {
                    Id =  Convert.ToInt16(reader["Id"]),
                    Name = reader["Name"]
                };
            cats.Add(cat);
            }
        }
        finally 
        {
            connection.Close();
        }
        return cats;
    }
}