Can I use the Win32 API from a .NET Framework program?

 
using System; 
using System.Runtime.InteropServices; 
 
class MainApp 
{ 
    [DllImport("user32.dll", EntryPoint="MessageBox")] 
    public static extern int MessageBox(int hWnd, String 
strMessage, String strCaption, uint uiType); 
 
    public static void Main() 
    { 
        MessageBox(0, "This is PInvoke in operation!", 
".NET", 0 ); 
    } 
}