C #, MySQL - kesalahan fatal terjadi selama eksekusi perintah- Memeriksa solusi lain, ada sesuatu yang saya Hilang

Baris ini salah

using (conn = new MySqlConnection(cs));

Hapus titik koma dan sertakan semua yang memerlukan variabel MySqlConnection di dalam {} blokir

using (MySqlConnection conn = new MySqlConnection(cs))
{
    // No need to test if the connection is not open....
    conn.Open();
    .........

    // Not needed (at least from your code above
    // MySqlDataAdapter MyAdapter2 = new MySqlDataAdapter();
    // MyAdapter2.SelectCommand = myCommand2;

    ... calcs follow here

    // Attention here, if the query returns null (no input match) this line will throw
    oldpoints = (int)myCommand2.ExecuteScalar();

    .... other calcs here


    MySqlCommand cmdDataBase = new MySqlCommand(query, conn);
    cmdDataBase.Parameters.Add("@input", SqlDbType.Int).Value = Convert.ToInt32(textBox2.Text);
    cmdDataBase.Parameters.AddWithValue("@Points", new_points);
    cmdDataBase.Parameters.AddWithValue("@Rewards", new_rewards);
    cmdDataBase.Parameters.AddWithValue("@Transaction", textBox3.Text);
    cmdDataBase.Parameters.AddWithValue("@TransationDate", transaction_date);

    // Use ExecuteNonQuery for INSERT/UPDATE/DELETE and other DDL calla
    cmdDataBase.ExecuteNonQuery();

    // Not needed
    // MySqlDataReader myReader2;
    // myReader2 = cmdDataBase.ExecuteReader();

    // Not needed, the using block will close and dispose the connection
    if(conn.State == ConnectionState.Open)
        conn.Close();

}

Ada juga kesalahan lain dalam kueri terakhir. Tidak ada spasi antara parameter @TransactionDate dan klausa WHERE. Dalam kasus di mana teks perintah SQL yang panjang diperlukan, saya merasa sangat berguna kelanjutan karakter baris string verbatim @

string query = @"UPDATE members Set [email protected], [email protected], 
                        [email protected], [email protected]
                        WHERE id = @input;";