c# - Fill generic list from SqlDataReader

Question

How can I add values that a SqlDataReader returns to a generic List? I have a method where I use SqlDataReader to get CategoryID from a

Answer 1

Try like this, it's better, safer, uses lazy loading, less code, working, ...:

public IEnumerable GetIds()
{
    using (var connection = new SqlConnection(connectionString))
    using (var cmd = connection.CreateCommand())
    {
        connection.Open();
        cmd.CommandText = "select CategoryID from Categories";
        using (var reader = cmd.ExecuteReader())
        {
            while (reader.Read())
            {
                yield return reader.GetInt32(reader.GetOrdinal("CategoryID"));
            }
        }
    }
}

and then:

List catIds = GetIds().ToList();