If, for example you want to send a message to you window to bring it to the top of the z-order, add the following code into your class declaration, e.g.:

  public class MyClass {

    private bool x = false;

   private static extern int BringWindowToTop(int hWnd);

The EntryPoint is not required - if omitted the entry point into the dll will be the name of the method.

To use the imported method, just call as normal, e.g.