asp.net - automatically change connection string. hosting -

when hosted site need change connection string.i have 2 connection string(for test on local computer,for hosting) can possible make switching connection string occurs automatically?

add reference add system.configuration:-

use connection string;

system.configuration.configurationmanager.connectionstrings["connstr"].connectionstring; 

place code in web config file;

<connectionstrings>   <add name="connstr"         connectionstring="server=localhost; database=foo; integrated security=true" ;        providername="system.data.sqlclient" /> </connectionstrings> 

have different connection strings in local , hosting once,after don't upload web config file hosting unless have to.