c# - 列名不能为空

Question

它下面是我的代码..我在平台上尝试了几个答案，但它仍然给我同样的错误..有人请帮帮我!!!!提前致谢!

public bool saveRecord(string Firstname,string Lastname,string Username,string Password,string Emailadress)
{
    using (MySqlConnection connection = new MySqlConnection("Server=localhost;Port=8889;Database=SSC;Uid=root;Password=root"))
    {
        try
        {
            string Sql_Query = "INSERT INTO administrator (Firstname,Lastname,Username,Password,EmailAdress)VALUES(@Firstname,@Lastname,@Username,@Password,@EmailAdress);";
            connection.Open();
            using (MySqlCommand command = new MySqlCommand(Sql_Query, connection))
            {
                command.Parameters.AddWithValue("@Firstname", Firstname);
                command.Parameters.AddWithValue("@Lastname", Lastname);
                command.Parameters.AddWithValue("@Username", Username);
                command.Parameters.AddWithValue("@Password", Password);
                command.Parameters.AddWithValue("@EmailAdress", Emailadress);

                command.ExecuteNonQuery();
                MessageBox.Show("Inserted");
            }
            return true;
        }
        catch (Exception ex)
        {
            MessageBox.Show(ex.Message);
            return false;
        }
    }
}

测试类.....

Models model = new Models();
if (model.saveRecord(TbFisrtname.Text, TbLastname.Text,TbUsername.Text,TbPassword.Text,TbAddress.Text) == true)
{
    MessageBox.Show("Inserted");
}

Answer 1

这表明 FirstName 参数变量在传递到方法时为 null。我建议这样验证你的论点:

    public bool saveRecord(string Firstname,string Lastname,string Username,string Password,string Emailadress)
    {

        if (string.IsNullOrWhiteSpace(FirstName))
           throw new ArgumentException(FirstName, "FirstName cannot be null");
        // Do the same for the other args...

        using (MySqlConnection connection = new MySqlConnection("Server=localhost;Port=8889;Database=SSC;Uid=root;Password=root"))
        {
            try
            {
                string Sql_Query = "INSERT INTO administrator (Firstname,Lastname,Username,Password,EmailAdress)VALUES(@Firstname,@Lastname,@Username,@Password,@EmailAdress);";
                connection.Open();    

                using (MySqlCommand command = new MySqlCommand(Sql_Query, connection))
                {

                    command.Parameters.AddWithValue("@Firstname", Firstname);
                    command.Parameters.AddWithValue("@Lastname", Lastname);
                    command.Parameters.AddWithValue("@Username", Username);
                    command.Parameters.AddWithValue("@Password", Password);
                    command.Parameters.AddWithValue("@EmailAdress", Emailadress);

                    command.ExecuteNonQuery();
                    MessageBox.Show("Inserted");

                }
                return true;
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
                return false;
            }
         }
     }