无法将“MySql.Data.MySqlClient.MySqlException”类型的对象转换为“System.IConvertible”类型。

Question

我找不到错误，我已经为这个问题工作了几个星期，我希望你能帮助我解决它。

这是我的访问数据库的类

namespace Monsterafood
{
    public class clsDataAccess : ClsWebConfig
    {

        public static DataTable ExecuteSelectCommand(DbCommand command)
        {
            DataTable table;
            try
            {
                command.Connection.Open();
                DbDataReader reader = command.ExecuteReader();
                table = new DataTable();
                table.Load(reader);
                reader.Close();
            }
            catch (Exception)
            {
                //clsUtilities.LogError(ex);
                throw;
            }
            finally
            {
                command.Connection.Close();
            }
            return table;
        }

        public static DbCommand CreateCommand()
        {
            string dataProviderName = ClsWebConfig.DbProviderName;
            string connectionString = ClsWebConfig.DbConnectionString;
            DbProviderFactory factory = DbProviderFactories.GetFactory(dataProviderName);
            DbConnection conn = factory.CreateConnection();
            conn.ConnectionString = connectionString;
            DbCommand comm = conn.CreateCommand();
            return comm;
        }

        public static int ExecuteNonQuery(DbCommand command)
        {
            int affectedRows = -1;
            try
            {
                command.Connection.Open();
                affectedRows = command.ExecuteNonQuery();
            }
            catch (Exception)
            {
                throw;
            }
            finally
            {
                command.Connection.Close();
            }
            return affectedRows;
        }

        public static string ExecuteScalar(DbCommand command)
        {
            string value = "";
            try
            {
                command.Connection.Open();
                value = command.ExecuteScalar().ToString();
            }
            catch (Exception)
            {
                throw;
            }
            finally
            {
                command.Connection.Close();
            }
            return value;
        }

    }
}

这是调用类的方法

public static string inserta(string id_add, string nombre, string precio)
        {
            DbCommand comm = clsDataAccess.CreateCommand();
            comm.CommandText= "INSERT INTO temporalcrepa(id_add, nombre, precio) VALUES(" + id_add + ", '" + nombre + "', " + precio + "); ";
            string x= clsDataAccess.ExecuteScalar(comm);
            return x;
        }

我正在使用 c# 和 javascript，我的数据库是 mysql。 非常感谢您帮我解决问题

Answer 1

你正在执行一个调用 executeScalar() 的插入语句，你想调用 ExecuteNonQuery() 而不是 Scalar。