C# Connection class

using System;
using System.Configuration;
using System.Data;
using System.Data.SqlClient;


namespace Pesquisa_boleto.Classes
{
    public class Dados
    {
        public static string erro = "";
        public static DataTable getDados(string sql, string connection = "")
        {
            DataTable dt = new DataTable();
            erro = "";
            try
            {
                using (SqlConnection con = getConexaoBD(connection))
                {
                    using (SqlCommand cmd = new SqlCommand(sql, con))
                    {
                        cmd.CommandType = CommandType.Text;
                        //con.Open();
                        //cmd.ExecuteNonQuery();
                        SqlDataAdapter da = new SqlDataAdapter(cmd);
                        da.Fill(dt);
                        return dt;
                    }
                }
            }
            catch (Exception ex)
            {
                erro = Util.Util.GetExceptionMessage(ex);
                throw ex;
            }
        }

        public static void setDados(string sql, string connection = "")
        {
            erro = "";
            try
            {
                using (SqlConnection con = getConexaoBD(connection))
                {
                    using (SqlCommand cmd = new SqlCommand(sql, con))
                    {
                        con.Open();
                        //con.ConnectionTimeout = 600;
                        cmd.ExecuteNonQuery();
                        con.Close();
                    }
                }
            }
            catch (Exception ex)
            {
                erro = Util.Util.GetExceptionMessage(ex);
                throw ex;
            }
        }

        public static DataTable execProcedure(string procedure, string[] parametros, string connection = "")
        {
            DataTable dt = new DataTable();
            erro = "";
            bool b = false;
            DateTime dtTemp = DateTime.Now;
            try
            {
                using (SqlConnection con = getConexaoBD(connection))
                {
                    using (SqlCommand cmd = new SqlCommand(procedure, con))
                    {
                        cmd.CommandType = CommandType.StoredProcedure;
                        cmd.CommandTimeout = 200;
                        con.Open();
                        SqlCommandBuilder.DeriveParameters(cmd);
                        for (int i = 0; i < parametros.Length; i++)
                        {
                            if (cmd.Parameters[i + 1].DbType == DbType.Boolean)
                            {
                                b = false;
                                if (bool.TryParse(parametros[i].ToString(), out b))
                                    cmd.Parameters[i + 1].Value = b;
                                else
                                    throw new Exception("Erro! Parâmetro " + cmd.Parameters[i + 1].ParameterName + " inválido.");
                            }
                            if (cmd.Parameters[i + 1].DbType == DbType.DateTime)
                            {
                                if (parametros[i].ToString() == "null" || string.IsNullOrWhiteSpace(parametros[i].ToString()))
                                    cmd.Parameters[i + 1].Value = DBNull.Value;
                                else
                                {
                                    if (DateTime.TryParse(parametros[i].ToString(), out dtTemp))
                                        cmd.Parameters[i + 1].Value = dtTemp;
                                    else
                                        throw new Exception("Erro! Parâmetro " + cmd.Parameters[i + 1].ParameterName + " inválido.");
                                }
                            }
                            else
                                cmd.Parameters[i + 1].Value = parametros[i].ToString();
                        }
                        SqlDataReader dr = cmd.ExecuteReader();
                        dt.Load(dr);

                        //while (!dr.IsClosed && dr.Read())
                        //{
                        //    dt.Load(dr);
                        //}

                        return dt;
                    }
                }
            }
            catch (Exception ex)
            {
                erro = Util.Util.GetExceptionMessage(ex);
                throw ex;
            }
        }

        public static string setDadosRetorno(string sql, string connection = "")
        {
            erro = "";
            try
            {
                using (SqlConnection con = getConexaoBD(connection))
                {
                    using (SqlCommand cmd = new SqlCommand(sql, con))
                    {
                        con.Open();
                        string Retorno = cmd.ExecuteScalar().ToString();
                        con.Close();
                        return Retorno;
                    }
                }
            }
            catch (Exception ex)
            {
                erro = Util.Util.GetExceptionMessage(ex);
                //return erro;
                throw ex;
            }
        }

        private static SqlConnection getConexaoBD(string connection)
        {
            if (string.IsNullOrWhiteSpace(connection))
                connection = "ConnectionStringName"; //conexão padrão

            //obtem a string de conexão do Web.Config e retorna uma nova conexao
            string strConexao = ConfigurationManager.ConnectionStrings[connection].ConnectionString;
            return new SqlConnection(strConexao);
        }
    }
}