Question

有没有办法在下面列出条件：

<h3 ng-show="ctrl.loggedIn">
{{ctrl.loggedInUser.FirstName + " " + ctrl.loggedInUser.LastName + " is logged in."}}
</h3>

如果 ctrl.loggedInUser.FirstName 未定义或 null ，则无法打印。

点击here访问github上的项目。

Answer 1

是的，你可以。使用

class Game < ApplicationRecord
  belongs_to :categorization

  validate :only_one_most_popular_game
  scope :most_popular, -> { where(most_popular: true) }

  protected

  def only_one_most_popular_game
    return unless most_popular?

    matches = Game.most_popular
    if persisted?
      matches = matches.where('id != ?', id)
    end
    if matches.exists?
      errors.add(:most_popular, 'Can\'t have another most popular game.')
    end
  end
end

在DOM中添加条件

ng-if

Answer 2

h3仅显示ctrl.loggedInUser.FirstName是否具有某个值

<h3 ng-show="ctrl.loggedIn && ( ctrl.loggedInUser.FirstName!=null || (ctrl.loggedInUser.FirstName!='undefined')")>
{{ctrl.loggedInUser.FirstName + " " + ctrl.loggedInUser.LastName + " is logged in."}}
</h3>

你也可以这样做

 <h3 ng-hide="!ctrl.loggedIn && (ctrl.loggedInUser.FirstName==null || (ctrl.loggedInUser.FirstName=='undefined')")>
    {{ctrl.loggedInUser.FirstName + " " + ctrl.loggedInUser.LastName + " is logged in."}}
    </h3>

Answer 3

您可以使用ng-show

<h3 ng-show="ctrl.loggedInUser.FirstName!=undefined || ctrl.loggedInUser.FirstName!=null">
{{ctrl.loggedInUser.FirstName + " " + ctrl.loggedInUser.LastName + " is logged in."}}
</h3>

Answer 4

<div ng-switch on="ctrl.loggedInUser.FirstName == null || ctrl.loggedInUser.FirstName == undefined || ctrl.loggedInUser.FirstName == ''">
    <h3 ng-switch-when="true">Please log in.</h3>
    <h3 ng-switch-when="false">{{ctrl.loggedInUser.FirstName + " " + ctrl.loggedInUser.LastName + " is logged in."}}</h3>
</div>

这对我有用。感谢所有的想法。

有条件的ng-show

4 个答案: