使用System.Configuration.ConfigurationManager类在app.config获取连接字符串

using System;
using System.Data;
using System.Data.SqlClient;

using System.Text;

using System.Configuration;

static void Main(string[] args)
{

　　string strCn;

　　//Get the connection string on app.config

　　strCn = ConfigurationManager.ConnectionStrings["ConsoleAppBooksMgr.Properties.Settings.BooksMgrConnectionString"//ConnectionStringName].ToString();

　　Console.WriteLine(strCn);

}