写一个C#mysql工具类

以下是一个简单的 C# MySQL 工具类的实现，包含了连接、查询和关闭数据库等基本操作：

using System;
using System.Data;
using MySql.Data.MySqlClient;

namespace MySqlUtils
{
    public class MySqlHelper
    {
        private readonly string connectionString; // 数据库连接字符串

        public MySqlHelper(string connectionString)
        {
            this.connectionString = connectionString;
        }

        // 执行查询，返回 DataTable
        public DataTable ExecuteQuery(string sql)
        {
            using (var connection = new MySqlConnection(connectionString))
            {
                connection.Open();
                var command = new MySqlCommand(sql, connection);
                var adapter = new MySqlDataAdapter(command);
                var dataTable = new DataTable();
                adapter.Fill(dataTable);
                return dataTable;
            }
        }

        // 执行非查询操作，返回受影响的行数
        public int ExecuteNonQuery(string sql)
        {
            using (var connection = new MySqlConnection(connectionString))
            {
                connection.Open();
                var command = new MySqlCommand(sql, connection);
                return command.ExecuteNonQuery();
            }
        }

        // 关闭数据库连接
        public void Close()
        {
            MySqlConnection.ClearAllPools(); // 清空连接池
        }
    }
}

使用示例：

using System;
using System.Data;
using MySqlUtils;

namespace Test
{
    class Program
    {
        static void Main(string[] args)
        {
            var connectionString = "server=localhost;uid=root;pwd=root;database=test;";
            var helper = new MySqlHelper(connectionString);

            // 查询
            var dataTable = helper.ExecuteQuery("SELECT * FROM users");
            foreach (DataRow row in dataTable.Rows)
            {
                Console.WriteLine(row["id"] + " " + row["name"]);
            }

            // 非查询操作
            var affectedRows = helper.ExecuteNonQuery("INSERT INTO users(name) VALUES('Test')");
            Console.WriteLine("Affected Rows: " + affectedRows);

            helper.Close();
        }
    }
}

注意：该示例中的连接字符串需要根据实际情况进行修改。