BackboneJS - Collection At

更新于 2025/12/3 19:11:00

描述

用于使用指定的索引从集合中检索模型。

语法

collection.at(index)

参数

index − 这是我们可以从集合中获取模型的索引位置。

示例

<!DOCTYPE html>
<html>
   <head>
      <title>Collection Example</title>
      <script src = "https://code.jquery.com/jquery-2.1.3.min.js"
         type = "text/javascript"></script>
      
      <script src = "https://cdnjs.cloudflare.com/ajax/libs/underscore.js/1.8.2/underscore-min.js"
         type = "text/javascript"></script>
      
      <script src = "https://cdnjs.cloudflare.com/ajax/libs/backbone.js/1.1.2/backbone-min.js"
         type = "text/javascript"></script>
   </head>
   
   <body>
      <script type = "text/javascript">
      
        //模型名称为"Player"，包含默认值
        var Player = Backbone.Model.extend ({
            defaults: {
                id:"",
                name: ""
            }
        });
        
        //"PlayersCollection"是集合的一个实例
        var PlayersCollection = Backbone.Collection.extend ({
            model: Player //模型"Player"是使用模型属性指定的
        });
        var player1 = new Player({id:1, name: "dhoni" });
        var player2 = new Player({id:2, name: "raina"});
        
        //add() 方法将模型"player1"和"player2"添加到集合实例"mycollection"中
        var mycollection = new PlayersCollection();
        mycollection.add([player1,player2]);
        document.write('<b>添加的Player为：</b> ' + JSON.stringify(mycollection.toJSON()));
        var player3 = new Player({id:3, name: "yuvraj" });
        
        //此处，将模型"player3"添加到集合的第 0 个索引处
        mycollection.add(player3,{at:0});
        
        //显示所有添加的模型。player3 将添加到第 0 个位置
        document.write('<br><b>现在新的Player列表为：</b> ' +
        JSON.stringify(mycollection.toJSON()));
      </script>
      
   </body>
</html>