ADO.NET - The Size property has an invalid size of 0

Question

I\'m trying to get output value from DB via ADO.NET. There\'s a client code:

    using (var connection = new SqlConnection(ConnectionString))
    {
                


        

Answer 1

you have to set Size for parameter output

using (var connection = new SqlConnection(ConnectionString))
{
    connection.Open();
    SqlCommand command = new SqlCommand("pDoSomethingParamsRes", connection);
    command.CommandType = CommandType.StoredProcedure;
    command.Parameters.Add("@i", 1);
    var outParam = new SqlParameter("@out", SqlDbType.VarChar);
    outParam.Direction = ParameterDirection.Output;
    outParam.Size = 50; // this is example
    command.Parameters.Add(outParam);
    command.ExecuteNonQuery();
    Console.WriteLine(command.Parameters["@out"].Value.ToString());
}