How to get a Mysql output Parameter via C#

Question

I researched and applied what I saw, but is giving error:

MySqlConnection con = new MySqlConnection(banco.Conexao);
MySqlCommand comando = new MySqlCommand("sp_venda", con);
comando.CommandType = System.Data.CommandType.StoredProcedure;

comando.Parameters.Add("usuario", MySqlDbType.Int32).Value = banco.Usuario;
comando.Parameters.Add("dinheiro", MySqlDbType.Double).Value = banco.formataDinheiro(Venda.Dinheiro);
comando.Parameters.Add("debito", MySqlDbType.Double).Value = banco.formataDinheiro(Venda.Dinheiro);
comando.Parameters.Add("credito", MySqlDbType.Double).Value = banco.formataDinheiro(Venda.Dinheiro);
comando.Parameters.Add("voucher", MySqlDbType.Double).Value = banco.formataDinheiro(Venda.Dinheiro);
comando.Parameters.Add("desconto", MySqlDbType.Double).Value = banco.formataDinheiro(VendaBLL.somaDescontos().ToString());
comando.Parameters.Add("troco", MySqlDbType.Double).Value = banco.formataDinheiro(Venda.Troco);

MySqlParameter paramHorario = new MySqlParameter("horario", MySqlDbType.Time);
paramHorario.Direction = System.Data.ParameterDirection.Output;

comando.Parameters.Add(paramHorario);

con.Open();
comando.ExecuteNonQuery();
Venda.Horario = comando.Parameters["horario"].Value.ToString();
con.Close();

The error occurs on the following line:

comando.ExecuteNonQuery();

The connection opens normally. The error returned is: "Formatexception: Input string was not in an incorrect format." What am I doing wrong?

Edit

 public static string formataDinheiro(string grana)
 {
   if (DetectaTipo(grana) == "null")
      return "null";

 return grana.Replace("R$ ", "").Replace(",", ".");
 }

Answer 1

It means that some of its parameters are not formatted as it should be. Its function banco.formataDinheiro() is not returning a Double, and yes a String. That’s why the mistake.

To work with money, the ideal is the type Decimal. The Double can bring complications, such as rounding problems.