C # Read and write operations data in app. Config

<?xml version="1.0" encoding="utf-8" ?>< configuration>  <connectionStrings>    <add name="SQL Server" connectionstring="Data source=wt01395\sqlexpress;initial catalog=mydb;integrated security=true  "/>  </connectionStrings>  <appSettings>    <add key="" />  </appSettings></configuration>

App.

References library for the introduction of configuration
Read
String constr = configurationmanager.connectionstrings["SQL Server"]. ToString ();

For saving data
Write  
Configuration config = configurationmanager.openexeconfiguration (configurationuserlevel.none);            Config. AppSettings.Settings.Remove ("Lastloginuser");            Config. APPSETTINGS.SETTINGS.ADD ("Lastloginuser", userName);            Config. Save ();
Only writes the value to the OesShareUI.exe.Config  will not be written on the source file

　　

C # Read and write operations data in app. Config