DLL with configuration file

Using configuration files in DLL is not trivial.
To accomplish this, we must follow these steps:

• Add a reference to System.Configuration
  
• Add a new Application Configuration File and the name it [Your project].dll.config
  
• Change the BuildAction property of the config file to Content
  
• Change the Copy to Output property to "Copy Always"
  

After these steps, you can access the configuration file this way:

//Open the configuration file using the dll location
Configuration myDllConfig = 
       ConfigurationManager.OpenExeConfiguration(this.GetType().Assembly.Location);
// Get the appSettings section
AppSettingsSection myDllConfigAppSettings = 
       (AppSettingsSection)myDllConfig.GetSection("appSettings");
// return the desired field 
return myDllConfigAppSettings.Settings["MyAppSettingsKey"].Value; 

Your configuration file should look like this:

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
  <appSettings>
    <add key ="MyAppSettingsKey" value="MyValue"/>
  </appSettings>
</configuration>

That's all. Hope you enjoy this tip.