class CustomTextField: UITextField {
  /// 是否只是用于显示（禁用粘贴、选择和全选功能）
  var displayOnly = false
  /// 禁用粘贴
  var disablePaste = false
  /// 禁用选择
  var disableSelect = false
  /// 禁用全选
  var disableSelectAll = false

  override func canPerformAction(action: Selector, withSender sender: AnyObject?) -> Bool {
    if displayOnly {
      return false
    }
    if disablePaste && action == #selector(paste(_:)) {
      return false
    }
    if disableSelect && action == #selector(select(_:)) {
      return false
    }
    if disableSelectAll && action == #selector(selectAll(_:)) {
      return false
    }
    return super.canPerformAction(action, withSender: sender)
  }
}