Partial Class Constructors

Is there a way to have a partial class' constructor call another method that my or may not be defined?

Basically my partial class constructor is defined:

public partial class Test
{
     public Test()
     {
          //do stuff
     }
}

I would like to be able to somehow insert extra code to be run after the class constructor is called.

In addition, is there a way to have more than one file to inject extra code after the constructor is called?