Application Configuration Files
Application configuration files contain settings specific to an application. This file contains configuration settings that the common language runtime reads (such as assembly binding policy, remoting objects, and so on), and settings that the application can read.
The name and location of the application configuration file depend on the application's host, which can be one of the following:
The configuration file for an application hosted by the executable host is in the same directory as the application. The name of the configuration file is the name of the application with a .config extension. For example, an application called myApp.exe can be associated with a configuration file called myApp.exe.config.
In Visual Studio projects, place the .config file in the project directory and set its Copy To Output Directory property to Copy always or Copy if newer. Visual Studio automatically copies the file to the directory where it compiles the assembly.
For more information about ASP.NET configuration files, see ASP.NET Configuration Settings
Internet Explorer-hosted application.
If an application hosted in Internet Explorer has a configuration file, the location of this file is specified in a <link> tag with the following syntax:
<link rel="ConfigurationFileName" href="location">
In this tag, location is a URL to the configuration file. This sets the application base. The configuration file must be located on the same Web site as the application.
Deploying a Runtime Application Using Internet Explorer
Configuration File Schema for the .NET Framework