[SQL ] C#不能寫入MYSQL

[rushcloud (嗚啦啦～)]

原本以為for迴圈裡面有寫錯了

不過 cmd.CommandText = "DELETE FROM rfid WHERE present='1'";

用這段指令去測試能不能刪掉表單裡面 present為1 的欄位

結果也沒有動作

是有哪邊程式碼打錯了嗎?

但是查詢那部份可以印出來

小弟第一次用C#連接MySQL

C#也才剛碰 問了蠢問題 請大家見諒

以下是C#的程式碼


using System;
using System.Data;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.Text;

using MySql.Data.MySqlClient;

namespace ConsoleApplication1
{
        class Program
        {
                static void Main(string[] args)
                {
                        MySqlConnection myConn;
                        MySqlCommand cmd;
                        MySqlDataReader dr;

                        ArrayList arrLocMonitor = new ArrayList();
                        ArrayList arrDB = new ArrayList();

                        arrLocMonitor.Add("a");
                        arrLocMonitor.Add("b");
                        arrLocMonitor.Add("c");
                        arrLocMonitor.Add("d");

                        myConn = new MySqlConnection();
                        myConn.ConnectionString = "database=computer;server=localhost;User
id=root; pwd=123";

                        string sql = string.Empty;

                        try
                        {

                                sql = "SELECT * FROM rfid WHERE present =
'0'";

                                myConn.Open();

                                cmd = new MySqlCommand(sql, myConn);

                                Console.WriteLine(cmd.ExecuteNonQuery().ToString());

                                dr = cmd.ExecuteReader();

                if (dr.HasRows)
                {
                    cmd.CommandText = "DELETE FROM rfid WHERE present='1'";

                    while (dr.Read())
                    {
                        string col1 = dr.GetString("account").ToString();
                        string col2 = dr.GetString("present").ToString();
                        string col3 = dr.GetString("classroom").ToString();
                        //string col1 = dr.GetString("id").ToString();
                        //string col2 = dr.GetString("st_number").ToString();
                        //string col3 = dr.GetString("st_status").ToString();
                        //cmd.CommandText = "UPDATE rfid SET
classroom='T3301',present='1' WHERE account=b";
                        Console.Write(col1 + " - " + col2 + " - " + col3);

                        if (!arrLocMonitor.Contains(col2))
                        {
                            Console.Write(" - TRUE\n");
                        }
                        else
                        {
                            Console.Write(" - FALSE\n");
                        }

                        arrDB.Add(col1);

                        for (int i = 0; i < arrLocMonitor.Count; i++)
                        {
                            if (arrDB.Contains(arrLocMonitor[i]) == false)
                            {
                                cmd.CommandText = "UPDATE rfid SET
classroom='T3301',present='1' WHERE account=" + arrLocMonitor[i];
                            }
                            else
                            {
                                break;
                            }

                        }





                    }
                    PrintArrayListElement(arrDB);
                }
                        }
                        catch (Exception e)
                        {
                                Console.WriteLine(e.Message.ToString());
                        }
                        finally
                        {
                                myConn.Close();
                        }
                }

        private static void PrintArrayListElement(ArrayList _ArrList)
        {

            for (int i = 0; i < _ArrList.Count; i++)
            {
                if (i != (_ArrList.Count - 1))
                {
                    Console.Write(_ArrList[i] + ", ");
                }
                else
                {
                    Console.Write(_ArrList[i]);
                }
            }

            Console.WriteLine();
        }
        }
}

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