Using Dapper Micro-ORM.

RepositoryDapper.cs

using System.Collections.Generic;
using System.Data;
using System.Linq;
using System.Text;
using Dapper;

public class Repository
{
    private readonly Func<IDbConnection> _connection;

    public Repository(Func<IDbConnection> connection)
    {
        _connection = connection;
    }

    public List<Caller> Get(string callerid)
    {
        var sqlBuilder = new StringBuilder();

        var query = sqlBuilder.Append("SELECT id, `last_name` as name FROM contacts ")
                        .Append(" WHERE phone_work =@callerid")
                        .ToString();

        try
        {
            using (var con = _connection())
            {
                return con.Query<Caller>(query, new { callerid }).ToList();
            }
        }
        catch (Exception exception)
        {
            return null;
        }
    }
}