c#操作MySql.Data.DLL

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data;
using MySql.Data.MySqlClient;
using System.IO;

namespace comback
{
    class ServerDataBase
    {
        MySqlConnection conn;
        string connString = "Persist Security Info=False;database=tldb;server=127.0.0.1;user id=root;pwd=123456";
        private void OpenConn()
        {
            try
            {
                conn = new MySqlConnection();
                conn.ConnectionString = connString;
                conn.Open();
            }
            catch (Exception ee)
            {
                System.Windows.Forms.MessageBox.Show("打开数据库异常：" + ee.Message);
            }
        }

        
        /// <summary>
        /// 修改功能
        /// </summary>
        /// <param name="sql">修改语句</param>
        /// <returns></returns>
        public int ExcuteUser(string sql)
        {
            MySqlCommand cmd = null;
            MySqlTransaction trans = null;
            int count = 0;
            try
            {
                if (conn == null || conn.State == ConnectionState.Closed)
                {
                    OpenConn();
                }

                cmd = conn.CreateCommand();
                cmd.CommandText = sql;

                //创建事务
                trans = conn.BeginTransaction();

                count = cmd.ExecuteNonQuery();

                //事务提交
                trans.Commit();
            }
            catch
            {
                //事务回滚
                trans.Rollback();
            }
            finally
            {
                if (conn != null && (conn.State != ConnectionState.Closed))
                {
                    cmd.Dispose();
                    conn.Close();
                    conn.Dispose();
                }
            }
            return count;
        }

        //检验登录用户
        public string CheckUser(string username,string password)
        {
            string role = "";
            MySqlCommand cmd = null;
            MySqlDataReader reader = null;
            try
            {
                if (conn == null || conn.State == ConnectionState.Closed)
                {
                    OpenConn();
                }

                cmd = conn.CreateCommand();
                cmd.CommandText = "select role from tluser where username='" + username + "' and password='" + password + "'";
                reader = cmd.ExecuteReader();
                if (reader.HasRows)
                {
                    if (reader.Read())
                    {
                        role = reader.GetString("role");
                    }
                }
                else
                {
                    role = "";
                }
            }
            catch (Exception ee)
            {
                System.Windows.Forms.MessageBox.Show("服务器检查登录的用户合法性时异常：" + ee.Message);
            }
            finally
            {
                if (conn != null && (conn.State != ConnectionState.Closed))
                {
                    if (reader.IsClosed)
                    {
                        reader.Close();
                        reader.Dispose();
                    }
                    cmd.Dispose();
                    conn.Close();
                    conn.Dispose();
                }
            }
            return role;
        }
    }
}

/// <summary>        /// 获得数据集DataSet        /// </summary>        /// <param name="ds"></param>        /// <param name="sql"></param>        /// <returns></returns>        public DataSet getDS(DataSet ds, string sql)        {            //打开连接            getConnection();            try            {                //查询结果                MySqlDataAdapter mda = new MySqlDataAdapter(sql, conn);                mda.Fill(ds, "data");            }            catch (System.Exception e)            {                MessageBox.Show("getDS()异常：" + e.Message);            }            finally            {                conn.Close();                conn.Dispose();            }            return ds;        }