我想做一个函数，它将生成6个随机数字彩票，然后插入数据库。如果我写2，10，23这样的数字。。。etc是可以执行查询的，但是如果我编写名称变量，比如lotto[0]，lotto[1]。。。程序抛出错误。谢谢你的帮助。

private void button1_Click(object sender, EventArgs e)
    {
        int check = 0;
        int[] lotto = new int[6];
        Random rand = new Random();
        for (int i = 0; i < lotto.Length;)
        {
            check = rand.Next(1, 49);
            if (!lotto.Contains(check))
            {
                lotto[i] = check;
                i++;
            }
        }

        string insertQuery = "INSERT INTO kupony VALUES(NULL, 1, lotto[0], lotto[1], lotto[2], lotto[3], lotto[4], lotto[5], -1, '2018-04-25', -1)";
        connection.Open();
        MySqlCommand command = new MySqlCommand(insertQuery, connection);
        try
        {
            if (command.ExecuteNonQuery() == 1)
            {
                //MessageBox.Show("Data Inserted");
            }
            else
            {
                //MessageBox.Show("Data Not Inserted");
            }
        }
        catch (Exception ex)
        {
            MessageBox.Show(ex.Message);
        }

        connection.Close();

    }