How to see how many files in draggingPasteboard?

I have a drag operation that only allows to drag a single file, and I want to capture this on "draggingEntered" like so:

- (NSDragOperation)draggingEntered:(id<NSDraggingInfo>)sender {
  if ([[sender draggingPasteboard] count]] == 1) {
    return NSDragOperationCopy;
  }
  else {
    return NSDragOperationNone;
  }
}

But count is not valid method or property, but I can't figure out what to replace it with, so which is the best way to see how many items there are on the draggingPasteboard? Should I get the array of filenames on the draggingPasteboard using something like propertyListForType: NSFilenamsPboardType, and then get the index of that, or is there a more clever way to do this?

If You want to use count You need to use pasteboardItems which is items array who response to count.

It can be done like this:

- (NSDragOperation)draggingEntered:(id<NSDraggingInfo>)sender {

    if([[[sender draggingPasteboard] pasteboardItems] count] == 1) {
        return NSDragOperationCopy;
    }
    else {
        return NSDragOperationNone;
    }
}