I'm pretty sure (although not 100% certain, so correct me if I'm wrong) that the picture box has no PDF support what so ever. To my understanding you'd either need a 3rd party API or a good knowledge of the PDF file structure so you could get it to display as a TIFF or something in the picture box.
I'm guessing it would be the same for the copy and pasting into a textbox. Again though, I'm not 100% certain on this.