主干模型未定义？

发布于 2024-12-26 05:56:59 字数 887 浏览 0 评论 0 原文

我不明白为什么当我运行 this.model.fetch() 时 this.model 会在 view.intialize() 中定义，而不是在 view.render() 中定义。

Chrome 开发者工具屏幕截图

define([
  'jquery',
  'underscore',
  'backbone',
  'text!templates/example.html'
], function($, _, Backbone, exampleTemplate){

  var exampleView = Backbone.View.extend({
    el: $('body'),
    initialize: function() {
      this.model.set({ _id: this.options.user_id });
      this.model.fetch({
        success: this.render,
        error: function(model, response) {
          console.log('ERROR FETCHING MODEL');
          console.log(model);
          console.log(response);
        }
      });
    },
    render: function() {
      console.log('HELLO FROM RENDER');
      console.log(this.model);
      console.log('GOODBYE FROM RENDER');
    }
  });

  return exampleView;

});

原文

I can't understand why this.model would be defined in view.intialize() when I run this.model.fetch() on it but not in view.render().

Chrome Developer Tools Screenshot

define([
  'jquery',
  'underscore',
  'backbone',
  'text!templates/example.html'
], function($, _, Backbone, exampleTemplate){

  var exampleView = Backbone.View.extend({
    el: $('body'),
    initialize: function() {
      this.model.set({ _id: this.options.user_id });
      this.model.fetch({
        success: this.render,
        error: function(model, response) {
          console.log('ERROR FETCHING MODEL');
          console.log(model);
          console.log(response);
        }
      });
    },
    render: function() {
      console.log('HELLO FROM RENDER');
      console.log(this.model);
      console.log('GOODBYE FROM RENDER');
    }
  });

  return exampleView;

});

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听不够的曲调 2025-01-02 05:56:59

这是因为 this 的绑定方式不同，因为 render 被用作回调，请将以下行作为 initialize 方法中的第一行来绑定 this 到渲染方法的当前视图：

_.bindAll(this,"render");

Underscore.js bindAll 函数

将对象上的许多方法（由 methodNames 指定）绑定到
每当调用它们时，都会在该对象的上下文中运行。非常
方便绑定将用作事件的函数
处理程序，否则将使用相当无用的 this 来调用。

It is because the this is being bound differently because render is being used as a callback, put the following line as the first line in your initialize method to bind this to the current view for the render method:

_.bindAll(this,"render");

Underscore.js bindAll function

Binds a number of methods on the object, specified by methodNames, to
be run in the context of that object whenever they are invoked. Very
handy for binding functions that are going to be used as event
handlers, which would otherwise be invoked with a fairly useless this.