&tag(Cocoa/ドラッグアンドドロップ);
self.register(forDraggedTypes: [kUTTypeURL as String])
override func draggingEntered(_ sender: NSDraggingInfo) -> NSDragOperation {
let pasteboard = sender.draggingPasteboard()
let filteringOptions = [NSPasteboardURLReadingContentsConformToTypesKey:NSImage.imageTypes()]
if pasteboard.canReadObject(forClasses: [NSURL.self], options: filteringOptions) {
return NSDragOperation.copy
}
return NSDragOperation() //alternatively: []
}