开发环境：VS2010

数据库：MySQL V5.5.42

连接器：Connector.NET V6.9

1. 新建工程(Windows Application)

2. 增加引用(MySql.Data)

3. 放置控件

1个TextBox，1个DataGrideView等等

4. 查询按钮事件

   private void btnSearch_Click(object sender, EventArgs e)
        {
            string connStr = string.Format(
     "server={0}; user id={1}; password={2}; database=test; pooling=false",
     "localhost", "root", "qaz1xsw2");
            try
            {
                conn = new MySqlConnection(connStr);
                conn.Open();

            }
            catch (MySqlException ex)
            {
                MessageBox.Show("没有找到数据库: " + ex.Message);
            }

            // 设置数据桥
            dataAdapter = new MySqlDataAdapter(
                edtSql.Text,
                conn);
            // SQL
            sqlCmdBuilder = new MySqlCommandBuilder(dataAdapter);
            // 建立数据表
            table = new DataTable();
            DataSet ds = new DataSet();

            // 填充数据到数据桥
            dataAdapter.Fill(ds);

            DataColumn dc = new DataColumn();
            dc.ColumnName = "序号";
            dc.AutoIncrement = true;
            dc.AutoIncrementSeed = 1;
            dc.AutoIncrementStep = 1;
            table.Columns.Add(dc);
            table.Merge(ds.Tables[0]);

            // 指定数据源
            dataGridView1.DataSource = table;
        }

运行效果

源代码：

Form1.cs

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

namespace WindowsFormsApplication2
{
    public partial class Form1 : Form
    {
        private MySqlConnection conn;
        private DataTable table;
        private MySqlDataAdapter dataAdapter;
        private MySqlCommandBuilder sqlCmdBuilder; 

        public Form1()
        {
            InitializeComponent();
        }

        private void btnSearch_Click(object sender, EventArgs e)
        {
            string connStr = string.Format(
     "server={0}; user id={1}; password={2}; database=test; pooling=false",
     "localhost", "root", "qaz1xsw2");
            try
            {
                conn = new MySqlConnection(connStr);
                conn.Open();

            }
            catch (MySqlException ex)
            {
                MessageBox.Show("没有找到数据库: " + ex.Message);
            }

            // 设置数据桥
            dataAdapter = new MySqlDataAdapter(
                edtSql.Text,
                conn);
            // SQL
            sqlCmdBuilder = new MySqlCommandBuilder(dataAdapter);
            // 建立数据表
            table = new DataTable();
            DataSet ds = new DataSet();

            // 填充数据到数据桥
            dataAdapter.Fill(ds);

            DataColumn dc = new DataColumn();
            dc.ColumnName = "序号";
            dc.AutoIncrement = true;
            dc.AutoIncrementSeed = 1;
            dc.AutoIncrementStep = 1;
            table.Columns.Add(dc);
            table.Merge(ds.Tables[0]);

            // 指定数据源
            dataGridView1.DataSource = table;
        }
    }
}

参考文章：《MySQL
Connector/Net 的简单使用》