You can get an
Icon
instance of said icon using
Icon.ExtractAssociatedIcon[
^], with the file path of the executable as argument (if it's your own executable, this file path is in
Assembly.GetExecutingAssembly().Location
with Assembly in System.Reflection).
To put it in the PictureBox, you'll have to convert it to a Bitmap using
Bitmap.FromHicon[
^] (usage:
Bitmap.FromHicon(yourIcon.Handle)
where
yourIcon
is the result of ExtractAssociatedIcon).