MysqlHelp

using System.Configuration;
using MySql.Data；

public class MySqlHelp
    {
        //链接字符串
        private static string connection = ConfigurationManager.ConnectionStrings["db"].ConnectionString;

        // 执行insert、delete、update的方法
        public static int ExcuteNonQuery(string sql, params DbParameter[] parameter)
        {
            using (MySqlConnection con = new MySqlConnection(connection))
            {
                if (con.State == ConnectionState.Closed)
                
                    con.Open();
               
                using (MySqlCommand cmd = new MySqlCommand(sql,con))
                {
                    if (parameter != null)
                    {
                        cmd.Parameters.AddRange(parameter);
                    }

                    return cmd.ExecuteNonQuery();
                }
            }
        }

        // 执行sql语句，返回单个值。
        public static object ExecuteScalar(string sql, params DbParameter[] parameters)
        {
            using (MySqlConnection con = new MySqlConnection(connection))
            {
                con.Open();
                using (var cmd = new MySqlCommand(sql,con))
                {
                    if (parameters != null)
                    {
                        cmd.Parameters.AddRange(parameters);
                    }
                    return cmd.ExecuteScalar();
                }
            }
        }

       //查询一个实例或列表
        public static MySqlDataReader ExecuteReader(string sql, params DbParameter[] parameters)
        {
            MySqlConnection con = new MySqlConnection(connection);
            using (MySqlCommand cmd = new MySqlCommand(sql, con))
            {
                if (parameters != null)
                {
                    cmd.Parameters.AddRange(parameters);
                }
                con.Open();
                return cmd.ExecuteReader(CommandBehavior.CloseConnection);
            }
        }

       //查询集合
        public static DataTable ExecuteDataTable(string sql, params DbParameter[] parameters)
        {
            SqlDataAdapter sqlAdapter = new SqlDataAdapter(sql, connection);
            if (parameters != null)
            {
                sqlAdapter.SelectCommand.Parameters.AddRange(parameters);
            }
            DataTable dt = new DataTable();
            sqlAdapter.Fill(dt);
            return dt;
        }
    }