System.Environment.SetEnvironmentVariable("MY_SETTING", "12345");
var path = System.Environment.GetEnvironmentVariable("PATH"); path += ";C:\\Program Files\\MyApp"; System.Environment.SetEnvironmentVariable("PATH", path);This code gets the current value of the "PATH" environment variable, appends ";C:\Program Files\MyApp" to it, and sets the new value. These examples use the System namespace, which is part of the .NET framework. Therefore, the package library is the .NET framework.