<connectionStrings>
    <add name="conn" connectionString="Data Source=123.206.101.218;Initial Catalog=MyShop;Persist Security Info=True;User ID=sa;Password=123456" providerName="System.Data.SqlClient" />
</connectionStrings>

调用方法：

using System;
using System.Collections.Generic;
using System.Configuration;
using System.Data.SqlClient;
using System.Linq;
using System.Runtime.CompilerServices;
using System.Web;
namespace MyShop
{
    class Db
    {
        public static SqlConnection GetConnection()
        {
            var connectionString = System.Configuration.ConfigurationManager.ConnectionStrings["conn"].ConnectionString;
            var conn = new SqlConnection(connectionString);
            return conn;
        }
    }
}