c# - Microsoft Visual Studio 表单应用程序 - mysql 错误

Question

我想从数据库中选择数据到我的表单应用程序中，但收到错误。

代码:

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using MySql.Data.MySqlClient;

namespace login
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }
        private void Form1_Load(object sender, EventArgs e)
        {
            MySqlConnection conn = DB_connect.getConect();
            MySqlCommand command = conn.CreateCommand();
            command.CommandText = "SELECT * FROM expeditori";
            conn.Open();
            DataSet a = new DataSet();
            MySqlDataAdapter b = new MySqlDataAdapter();
            b.Fill(a, "data");
            dataGridView1.DataSource = a;
            dataGridView1.DataMember = "data";
            conn.Close();
        }
    }
}

Answer 1

您可以尝试像这样更改代码:

代码

        try
        {
            dt = new DataTable();
            using (MySqlConnection conn = new MySqlConnection("datasource=localhost;port=3306;username=root;password=password"))
            {
                conn.Open();
                using (MySqlCommand cmd = new MySqlCommand())
                {
                    cmd.Connection = conn;
                    cmd.CommandText = "SELECT * FROM `tablename`.`expeditori`";
                    MySqlDataAdapter da = new MySqlDataAdapter(cmd);
                    da.Fill(dt);
                }
                conn.Close();
            }

            dataGridView1.DataSource = dt;
        }

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

希望这能解决您的问题!祝你今天过得愉快。 :)