swift - 在 Swift 中从 NSTextField 获取 NSImage

Question

我曾经像这样从 Obj-C 中检索 NSTextField 的子类中的 NSImage:

  NSDictionary *attributedVal = [[self attributedStringValue] attributesAtIndex:i effectiveRange:&effectiveRange];
  if ([[attributedVal allKeys] containsObject:NSAttachmentAttributeName]) {
    NSTextAttachment *attachment = [attributedVal valueForKey:NSAttachmentAttributeName];
    NSCell *attachmentCell = (NSCell *)[attachment attachmentCell];
    ... [[attachmentCell image] name] ...
  } 

当我尝试在 Swift 中做同样的事情时，我似乎无法转换 attachmentCell 但出现编译器错误:

  let attributedVal = attributedStringValue.attributesAtIndex(i, effectiveRange: effectiveRange)
  if let attachment = attributedVal[NSAttachmentAttributeName] as? NSTextAttachment {
    let attachmentCell = attachment.attachmentCell as NSCell // does not work
    ...
  }

Answer 1

感谢内特·库克。以下作品:

  let attributedVal = attributedStringValue.attributesAtIndex(i, effectiveRange: effectiveRange)
  if let attachment = attributedVal[NSAttachmentAttributeName] as? NSTextAttachment {
    let attachmentCell = attachment.attachmentCell as NSTextAttachmentCell
    let image = attachmentCell.image
    ...
  }